Enhanced Stability of Pd/ZnO Catalyst for CO Oxidative Coupling to Dimethyl Oxalate: Effect of Mg2+ Doping

Selectivity Control in the Direct CO Esterification over Pd@UiO-66: The Pd Location Matters

The selectivity control of Pd nanoparticles (NPs) in the direct CO esterification with methyl nitrite toward dimethyl oxalate (DMO) or dimethyl carbonate (DMC) remains a grand challenge. Herein, Pd NPs are incorporated into isoreticular metal-organic frameworks (MOFs), namely UiO-66-X (X=-H, -NO2 , -NH2 ), affording Pd@UiO-66-X, which unexpectedly exhibit high selectivity (up to 99 %) to DMC and regulated activity in the direct CO esterification. In sharp contrast, the Pd NPs supported on the MOF, yielding Pd/UiO-66, displays high selectivity (89 %) to DMO as always reported with Pd NPs. Both experimental and DFT calculation results prove that the Pd location relative to UiO-66 gives rise to discriminated microenvironment of different amounts of interface between Zr-oxo clusters and Pd NPs in Pd@UiO-66 and Pd/UiO-66, resulting in their distinctly different selectivity. This is an unprecedented finding on the production of DMC by Pd NPs, which was previously achieved by Pd(II) only, in the direct CO esterification.

Pattern Recognition with Temperature Regulation: A Single YSZ-Based Mixed Potential Sensor Classifies Multiple Mixtures of Isoprene, n-Propanol, and Acetone

Gas sensors integrated with machine learning algorithms have aroused keen interest in pattern recognition, which ameliorates the drawback of poor selectivity on a sensor. Among various kinds of gas sensors, the yttria-stabilized zirconia (YSZ)-based mixed potential-type sensor possesses advantages of low cost, simple structure, high sensitivity, and superior stability. However, as the number of sensors increases, the increased power consumption and more complicated integration technology may impede their extensive application. Herein, we focus on the development of a single YSZ-based mixed potential sensor from sensing material to machine learning for effective detection and discrimination of unary, binary, and ternary gas mixtures. The sensor that is sensitive to isoprene, n-propanol, and acetone is manufactured with the MgSb2O6 sensing electrode prepared by a simple sol-gel method. Unique response patterns for specific gas mixtures could be generated with temperature regulation. We chose seven algorithm models to be separately trained for discrimination. In order to realize more accurate discrimination, we further discuss the selection of suitable feature parameters and its reasons. With temperature regulation coefficients which are easily available as feature input to model, a single sensor is verified to achieve elevated accuracy rates of 95 and 99% for the discrimination of seven gases (three unary gases, three binary gas mixtures, and one ternary gas mixture) and redefined six gas mixtures. This article provides a potential new approach via a mixed potential sensor instead of a sensor array that could provide a wide application prospect in the field of electronic nose and artificial olfaction.

Recent advances in the routes and catalysts for ethanol synthesis from syngas

Ethanol, as one of the important bulk chemicals, is widely used in modern society. It can be produced by fermentation of sugar, petroleum refining, or conversion of syngas (CO/H₂). Among these approaches, conversion of syngas to ethanol (STE) is the most environmentally friendly and economical process. Although considerable progress has been made in STE conversion, control of CO activation and C-C growth remains a great challenge. This review highlights recent advances in the routes and catalysts employed in STE technology. The catalyst designs and pathway designs are summarized and analysed for the direct and indirect STE routes, respectively. In the direct STE routes (i.e., one-step synthesis of ethanol from syngas), modified catalysts of methanol synthesis, modified catalysts of Fischer-Tropsch synthesis, Mo-based catalysts, noble metal catalysts and multifunctional catalysts are systematically reviewed based on their catalyst designs. Further, in the indirect STE routes (i.e., multi-step processes for ethanol synthesis from syngas via methanol/dimethyl ether as intermediates), carbonylation of methanol/dimethyl ether followed by hydrogenation, and coupling of methanol with CO to form dimethyl oxalate followed by hydrogenation, are outlined according to their pathway designs. The goal of this review is to provide a comprehensive perspective on STE technology and inspire the invention of new catalysts and pathway designs in the near future.

Ambient-pressure synthesis of ethylene glycol catalyzed by C60-buffered Cu/SiO2

Bulk chemicals such as ethylene glycol (EG) can be industrially synthesized from either ethylene or syngas, but the latter undergoes a bottleneck reaction and requires high hydrogen pressures. We show that fullerene (exemplified by C₆₀) can act as an electron buffer for a copper-silica catalyst (Cu/SiO₂). Hydrogenation of dimethyl oxalate over a C₆₀-Cu/SiO₂ catalyst at ambient pressure and temperatures of 180° to 190°C had an EG yield of up to 98 ± 1%. In a kilogram-scale reaction, no deactivation of the catalyst was seen after 1000 hours. This mild route for the final step toward EG can be combined with the already-industrialized ambient reaction from syngas to the intermediate of dimethyl oxalate.

A predicted new catalyst to replace noble metal Pd for CO oxidative coupling to DMO

The reaction mechanisms of CO oxidative coupling to dimethyl oxalate (DMO) on different β-Mo2C(001) based catalysts have been studied by the density functional theory (DFT) method.

Enhancing the activity of Pd/Zn–Al–O catalysts for esterification of CO to dimethyl oxalate via increasing oxygen defects by tuning the Zn/Al ratio

The enhancement of oxygen defects in the spinel support is the essential reason for the improvement of catalytic activity, which reveals the support effect of catalyst for CO direct esterification to dimethyl oxalate.

Fabrication of AgNi Nano-alloy-Decorated ZnO Nanocomposites as an Efficient and Novel Hybrid Catalyst to Degrade Noxious Organic Pollutants

Contamination through industrial effluents is a major threat to the environment. Degradation of organic pollutants remains a major challenge, and semiconductor-based catalysis is reported to be a viable solution. Recently, AgNi bimetallic alloy nanoparticles attracted great attention with superior properties. We report the synthesis of AgNi nano-alloy particles immobilized over the surface of ZnO hexagonal rods through an in situ chemical co-reduction process to develop a novel AgNi@ZnO nanocomposite for catalytic applications. The crystal structure, phase purity, morphology, particle size, and other properties of the as-synthesized AgNi@ZnO nanocomposite were scrutinized using powder X-ray diffraction, scanning electron microscopy, Raman spectroscopy, energy-dispersive X-ray analysis, multipoint Brunauer-Emmett-Teller, and transmission electron microscopy. The composite exhibits excellent catalytic activity toward the reduction of nitroarenes and environment polluting organic dyes. The synthesized nanocomposite shows enhanced catalytic activity with an incredible reaction rate constant, noticeable low degradation time, and greater stability. The catalyst is easily recyclable and exhibits consecutive catalytic cycle usage.

Enhanced metal-support interaction between Pd and hierarchical Nb2O5via oxygen defect induction to promote CO oxidative coupling to dimethyl oxalate

Production of ethylene glycol from coal is a particularly interesting route as it is an economic alternative to the petrochemical-based route. In this process, effectively generating dimethyl oxalate (DMO) is a crucial step by CO oxidative coupling reaction under Pd-based catalysts. However, the aggregation of Pd species over the support is still an issue that relates to the deterioration of catalytic activity and stability. To this end, enhancing the metal-support interaction is urgently required. In this work, hierarchical Nb₂O₅ (H-Nb₂O₅) microspheres with abundant oxygen defects were synthesized to anchor the Pd species thus promoting the electron transfer between Pd species and Nb species associated with the generation of interfacial Pd-NbO_x sites. Besides, the thinned electron density of Pd species resulting from the electron-withdrawing effect of Nb species is beneficial for activating the adsorbed CO molecules, leading to superior catalytic activity. The Pd/H-Nb₂O₅ catalyst exhibited 63.1% of CO conversion (theoretical maximum conversion: 64.3%) and 92.9% of DMO selectivity, with a DMO weight time yield of 1297.9 g kg_cat.^-1 h^-1, and remained robust even after 50 h of time on stream evaluation. Current work provides a deep insight into the CO activation mechanism and helps improve the catalytic stability by boosting interfacial electron interaction via oxygen defects induction, and also sheds light on the design and synthesis of high-performance catalysts in other heterogeneous catalysis fields.

Highly Effective Pd/MgO/γ-Al2O3 Catalysts for CO Oxidative Coupling to Dimethyl Oxalate: The Effect of MgO Coating on γ-Al2O3

The support of MgO/γ-Al₂O₃ was initially prepared by a multiple impregnation method and Pd was placed on the surface of the MgO/γ-Al₂O₃ support via incipient wetness impregnation. Pd/MgO/γ-Al₂O₃ (Pd/MAO) catalysts were systematically characterized by X-ray diffraction (XRD), Brunauer-Emmett-Teller (BET), CO₂-temperature-programmed desorption (TPD), transmission electron microscopy (TEM), CO-Fourier transform infrared (CO-FTIR), and X-ray photoelectron spectroscopy (XPS) and tested in the CO oxidative coupling to dimethyl oxalate (DMO) reaction. Compared to Pd/γ-Al₂O₃, the catalytic activities of the Pd/MAO catalysts improved significantly. The Pd/MAO catalyst with a 30% mass ratio of Mg to γ-Al₂O₃ delivers 3 times higher STY of DMO than that of Pd/γ-Al₂O₃. It has been demonstrated that MgO covered γ-Al₂O₃ layer-by-layer forming MAO supports, which can increase surface basicity and the interaction between Pd particles and the MAO supports. Moreover, the relationship between metal and support interaction and catalytic performance was discussed.

Boosting Interfacial Electron Transfer between Pd and ZnTi-LDH via Defect Induction for Enhanced Metal-Support Interaction in CO Direct Esterification Reaction

Strong metal-support interaction is crucial to the stability of catalysts in heterogeneous catalysis. However, reports on boosting interfacial electron transfer between metal and support via defect induction for enhanced metal-support interaction are limited. In this work, ultrathin reducible ZnTi-layered double hydroxide (LDH) nanosheets with rich oxygen defects were synthesized to stabilize Pd clusters, and the rich oxygen defects promoted Pd cluster bonding with Zn and Ti atoms in supports, thereby forming a metal-metal bond. Electron spin resonance (ESR), X-ray absorption fine spectra (XAFS), and density functional theory (DFT) calculations demonstrate remarkable interfacial electron transfer (0.62 e). The Pd/ZnTi-LDH catalyst shows superior catalytic stability for CO direct esterification to dimethyl oxalate. By contrast, the nonreducible Pd/ZnAl-LDH catalyst with a few oxygen defects shows minimal interfacial electron transfer (0.08 e), which leads to relatively poor catalytic stability. This work provides a deep insight into promoting the stability of catalysts by boosting interfacial electron transfer via defect induction.

Study on Ammonia-induced Catalyst Poisoning in the Synthesis of Dimethyl Oxalate

On an industrial plant, we observed and examined the ammonia-poisoning catalyst for the synthesis of dimethyl oxalate (DMO). We investigated the catalytic activity in response to the amount of ammonia and revealed the mechanism of such poisoning by X-ray photoelectron spectroscopy (XPS) characterization. Our results show that only 0.002% ammonia in the feed gas can significantly deactivate the Pd-based catalyst. Two main reasons were proposed: one is that the competitive adsorption of ammonia on the active component Pd hinders the carbon    monoxide (CO) coupling reaction and the redox cycle between Pd0 and Pd2+; and the other is that the high-boiling nitrogen-containing amine compounds formed by reacting with ammonia have adsorbed on the catalyst, which hinders the progress of the catalytic reaction. The deactivation caused by the latter is irreversible. The catalytic activity can be completely restored by a low-temperature liquid-phase in-situ regeneration treatment. Copyright © 2021 by Authors, Published by BCREC Group. This is an open access article under the CC BY-SA License (https://creativecommons.org/licenses/by-sa/4.0). 

CO direct esterification to dimethyl oxalate and dimethyl carbonate: the key functional motifs for catalytic selectivity

The direct esterification of CO involves processes using CO as the starting material and ester chemicals as products. Dimethyl oxalate (DMO) and dimethyl carbonate (DMC) are two different products of the direct CO esterification reaction. However, the effective control of the reaction pathway and direct synthesis of DMO and DMC are challenging. In this review, we summarize the recent research progress on the direct esterification of CO to DMO/DMC and reveal the functional motifs responsible for the catalytic selectivity. Firstly, we discuss the microstructure of catalysts for the direct esterification of CO to DMO and DMC, including the valence state and the aggregate state of Pd. Then, the influence of characteristics of the support on the selectivity is analyzed. Importantly, the aggregate state of the active component, Pd is deemed as a vital functional motif for catalytic selectivity. The isolated Pd is conducive for the formation of DMC, while the aggregated Pd is beneficial for the formation of DMO. This review will provide rational guidance for the direct esterification of CO to DMO and DMC.

Zn2+ stabilized Pd clusters with enhanced covalent metal-support interaction via the formation of Pd-Zn bonds to promote catalytic thermal stability

Pd-Based heterogeneous catalysts have been demonstrated to be efficient in numerous heterogeneous reactions. However, the effect of the support resulting in covalent metal-support interaction (CMSI) has not been researched sufficiently. In this work, a Lewis base is modulated over MgAl-LDH to investigate the support effects and it is further loaded with Pd clusters to research the metal-support interactions. MgAl-LDH with ultra-low Pd loading (0.0779%) shows CO conversion (55.0%) and dimethyl oxalate (DMO) selectivity (93.7%) for CO oxidative coupling to DMO, which was gradually deactivated after evaluation for 20 h. To promote the stability of Pd/MgAl-LDH, Zn2+ ions were introduced into the MgAl-LDH support to strengthen the CMSI by forming Pd-Zn bonds, which further increased the adsorption energy of the Pd clusters on ZnMgAl-LDH, and this was verified by X-ray absorption fine structure (XAFS) measurements and density functional theory (DFT) calculations. The stability of the Pd/ZnMgAl-LDH catalyst could be maintained for at least 100 h. This work highlights that covalent metal-support interactions can be strengthened by forming new metal-metal bonds, which could be extended to other systems for the stabilization of noble metals over supports.

Zn-Promoted Selective Gas-Phase Hydrogenation of Tertiary and Secondary C4 Alkynols over Supported Pd

We have investigated the gas-phase (P = 1 atm; T = 373 K) hydrogenation of (tertiary alkynol) 2-methyl-3-butyn-2-ol (MBY) and (secondary) 3-butyn-2-ol (BY) over a series of carbon (C), non-reducible (Al₂O₃ and MgO), and reducible (CeO₂ and ZnO) supported monometallic [Pd (0.6-1.2% wt) and Zn (1% wt)] and bimetallic Pd-Zn (Pd:Zn mol ratio = 95:5, 70:30, and 30:70) catalysts synthesized by deposition-precipitation and colloidal deposition. The catalysts have been characterized by H₂ chemisorption, hydrogen temperature-programmed desorption (H₂-TPD), specific surface area (SSA), X-ray photoelectron spectroscopy (XPS), and transmission (TEM) and scanning transmission electron microscopy (STEM) analyses. Reaction over these catalysts generated the target alkenol [2-methyl-3-buten-2-ol (MBE) and 3-buten-2-ol (BE)] through partial hydrogenation and alkanol [2-methyl-butan-2-ol (MBA) and 2-butanol (BA)]/ketone [2-butanone (BONE)] as a result of full hydrogenation and double-bond migration. The catalysts exhibit a similar Pd nanoparticle size (2.7 ± 0.3 nm) but a modified electronic character (based on XPS). Hydrogenation activity is linked to surface hydrogen (from H₂ chemisorption and H₂-TPD). An increase in H₂:alkynol (from 1 → 10) results in enhanced alkynol consumption with a greater rate in the transformation of MBY (vs BY); H₂:alkynol had negligible effect on product distribution. Reaction selectivity is insensitive to the Pd site electron density with a similar response (S_MBE = 65 ± 9% and S_BE = 70 ± 8%) over Pd^δ- (on Al₂O₃ and MgO) and Pd^δ+ (on C and CeO₂). A Pd/ZnO catalyst delivered enhanced alkenol selectivity (S_MBE = 90% and S_BE = 96%) attributed to PdZn alloy phase formation (proved by XRD and XPS) but low activity, ascribed to metal encapsulation. A two-fold increase in the consumption rate was recorded for Pd-Zn/Al₂O₃ (30:70) versus Pd/ZnO with a similar alloy content (32 ± 4% from XPS), ascribed to a contribution due to spillover hydrogen (from H₂-TPD) where high alkenol selectivity was maintained.

Gamma radiation-assisted in situ synthesis of palladium nanoparticles supported on ethylenediamine-functionalized polypropylene fabric as an efficient catalyst for reduction of 4-nitrophenol

Immobilization of Pd nanometals on a functionalized non-woven polypropylene fabric offers heterogenous catalytic activity in many chemical transformations and convenient separation from the reaction mixture.

Effect of Cu loading on the structural evolution and catalytic activity of Cu–Mg/ZnO catalysts for dimethyl oxalate hydrogenation

Proper Cu loading introduced into the Cu–Mg/ZnO system facilitates strengthening of the Cu–Zn synergistic effect and optical surface chemical properties.

Controlled Synthesis and Enhanced Catalytic Activity of Well-Defined Close-Contact Pd-ZnO Nanostructures

In this study, PdZn-ordered intermetallic nanoparticles (NPs) were prepared in liquid phase by butyllithium co-reduction of their precursors at 240 °C. Through calcination and subsequent reduction with H₂, the synthesized PdZn NPs were then in situ transformed into Pd-ZnO heteroaggregate nanocatalysts on alumina supports. Various characterization techniques, such as diffuse reflectance Fourier transform infrared with CO probes, transmission electron microscopy, X-ray diffraction, H₂ temperature-programmed reduction, and X-ray photoelectron spectra, reveal that PdZn NPs are ordered intermetallic compounds, and in situ transformation of PdZn alloy NPs results in close-contact Pd-ZnO heteroaggregates, where the interfaces are highly active and the interaction between Pd and ZnO prevents the active particles from agglomeration. The catalytic hydrogenations of nitrophenols over Pd/Al₂O₃ and Pd-ZnO/Al₂O₃ were investigated. The results show that Pd-ZnO/Al₂O₃ illustrates an enhanced catalytic activity relative to Pd/Al₂O₃, and no obvious activity degradation was observed in the recycle catalytic experiments over such nanostructures. It is concluded that the Pd-ZnO interaction not only enhances the catalytic hydrogenation activity but also promotes the thermal and catalytic stability.

Well-defined Pd anchoring on the surface of porous ZnO nanocomposites with excellent photocatalytic activity and good reusability for the removal of phenol from water

Well-defined Pd/ZnO nanocomposites prepared by modifying ZnO nanosheets with Pd nanoparticles exhibit excellent photocatalytic activity and good reusability for the removal of phenol from water.

Internally Supported Metal-Oxide Nanocatalyst for Hydrogenation of Nitroaromatics

The uncalcined but highly dispersive oxide-supported metal catalyst for liquid phase reactions may suffer from the agglomeration of metal nanoparticles and the drop of metal catalyst in solution, which will decrease the activity and shorten their life in catalysis. Here, a one-pot successive polyol reaction was developed to prepare M-E _xO _y colloidal particles as heterogeneous nanocatalysts, which merge the controlled synthesis of metal catalysts and oxide supports, the in situ loading of catalyst, and even the mesopore amplification into a highly integrated process. Unlike the traditional surface-deposited catalysts, the noble metal nanoparticles even with a large amount of loading are internally dispersed in the mesoporous oxide particles, which show higher activity and stability in the hydrogenation of nitroaromatics compared to the isolated nanocatalysts or surface-deposited catalysts. The improved activity and stability comes from the physical confinement of metal nanoparticles and good mass transportation of substrate/product within the support particles. This work proposed a novel method to prepare highly dispersed metal catalysts, which could be potentially useful to heterogeneous catalytic reactions with high-throughput and long-life demands.

Stability investigation of a high number density Pt1/Fe2O3 single-atom catalyst under different gas environments by HAADF-STEM

Catalysis by supported single metal atoms has demonstrated tremendous potential for practical applications due to their unique catalytic properties. Unless they are strongly anchored to the support surfaces, supported single atoms, however, are thermodynamically unstable, which poses a major obstacle for broad applications of single-atom catalysts (SACs). In order to develop strategies to improve the stability of SACs, we need to understand the intrinsic nature of the sintering processes of supported single metal atoms, especially under various gas environments that are relevant to important catalytic reactions. We report on the synthesis of high number density Pt₁/Fe₂O₃ SACs using a facial strong adsorption method and the study of the mobility of these supported Pt single atoms at 250 °C under various gas environments that are relevant to CO oxidation, water-gas shift, and hydrogenation reactions. Under the oxidative gas environment, Fe₂O₃ supported Pt single atoms are stable even at high temperatures. The presence of either CO or H₂ molecules in the gas environment, however, facilitates the movement of the Pt atoms. The strong interaction between CO and Pt weakens the binding between the Pt atoms and the support, facilitating the movement of the Pt single atoms. The dissociation of H₂ molecules on the Pt atoms and their subsequent interaction with the oxygen species of the support surfaces dislodge the surface oxygen anchored Pt atoms, resulting in the formation of Pt clusters. The addition of H₂O molecules to the CO or H₂ significantly accelerates the sintering of the Fe₂O₃ supported Pt single atoms. An anchoring-site determined sintering mechanism is further proposed, which is related to the metal-support interaction.

CO oxidative coupling to dimethyl oxalate over Pd-Me (Me = Cu, Al) catalysts: a combined DFT and kinetic study

CO oxidative coupling to dimethyl oxalate (DMO) on Pd(111), Pd-Cu(111) and Pd-Al(111) surfaces was systematically investigated by means of density functional theory (DFT) together with periodic slab models and micro-kinetic modeling. The binding energy results show that Cu and Al can be fine substrates to stably support Pd. The favorable pathway for DMO synthesis on these catalysts starts from the formation of two COOCH₃ intermediates, followed by the coupling to each other, and the catalytic activity follows the trend of Pd-Al(111) > Pd(111) > Pd-Cu(111). Additionally, the formation of DMO is far favorable than that of dimethyl carbonate (DMC) on these catalysts. The results were further demonstrated by micro-kinetic modeling. Therefore, Pd-Al bimetallic catalysts can be applied in practice to effectively enhance the catalytic performance and greatly reduce the cost. This study can help with fine-tuning and designing of high-efficient and low-cost Pd-based bimetallic catalysts.

Iron-doped ZnO as a support for Pt-based catalysts to improve activity and stability: enhancement of metal–support interaction by the doping effect

In heterogeneous catalysis, the role of the interface between a metal and a metal oxide in deciding catalytic performance has remained a long-standing question. Out of many molecular-scale factors that affect the properties of metal–oxide interfaces, doping or impurities in the oxides can result in excess charge carriers or oxygen vacancies on the oxides, which lead to a change in catalytic activity. For a model system with a tunable dopant, we employed Pt nanoparticles with Fe doping. We synthesized a series of Fe-doped ZnO with different Fe loadings (i.e., 0, 1, and 4%) using the co-precipitation method, and then deposited Pt nanoparticles onto these supports. The Pt-based catalysts were employed to investigate the effect of the dopant to promote the catalytic performance for the CO oxidation reaction. The 4% Fe loading sample showed the highest catalytic activity among the catalysts, with a turnover frequency of 5.37 s⁻¹ at 126 °C. The dopant was found to enhance the interaction between the Pt nanoparticles and the catalyst support, including the prevention of metal sintering, which resulted in an improvement of catalytic activity.

We deposited Pt nanoparticles on a series of Fe-doped ZnO with different Fe loadings to study the effect of dopant on the catalytic performance for the CO oxidation reaction.

Synthesis of Cu–Mg/ZnO catalysts and catalysis in dimethyl oxalate hydrogenation to ethylene glycol: enhanced catalytic behavior in the presence of a Mg2+ dopant

Mg²⁺ doped nanoscale Cu–Mg/ZnO catalysts prepared by the co-precipitation method have been systematically characterized focusing on the amount of Mg²⁺ ions incorporated.

Novel Metal Nanomaterials and Their Catalytic Applications

In the rapidly developing areas of nanotechnology, nano-scale materials as heterogeneous catalysts in the synthesis of organic molecules have gotten more and more attention. In this review, we will summarize the synthesis of several new types of noble metal nanostructures (FePt@Cu nanowires, Pt@Fe₂O₃ nanowires and bimetallic Pt@Ir nanocomplexes; Pt-Au heterostructures, Au-Pt bimetallic nanocomplexes and Pt/Pd bimetallic nanodendrites; Au nanowires, CuO@Ag nanowires and a series of Pd nanocatalysts) and their new catalytic applications in our group, to establish heterogeneous catalytic system in "green" environments. Further study shows that these materials have a higher catalytic activity and selectivity than previously reported nanocrystal catalysts in organic reactions, or show a superior electro-catalytic activity for the oxidation of methanol. The whole process might have a great impact to resolve the energy crisis and the environmental crisis that were caused by traditional chemical engineering. Furthermore, we hope that this article will provide a reference point for the noble metal nanomaterials' development that leads to new opportunities in nanocatalysis.