Augmented photocatalysis induced by 1T-MoS2 bridged 2D/2D MgIn2S4@1T/2H-MoS2 Z-scheme heterojunction: mechanistic insights into H2O2 and H2 evolution

In the realm of composite photocatalysts, the fusion of the co-catalyst effect with interfacial engineering is recognized as a potent strategy for facilitating the segregation and migration of photo-induced charge carriers. Herein, an innovative mediator-based Z-scheme hybrid, i.e. MIS@1T/2H-MoS2, has been well designed by pairing MIS with 1T/2H-MoS2via a facile hydrothermal strategy as a competent photocatalyst for H2O2 and H2 generation. The co-catalyst, i.e. metallic 1T-phase bridging between semiconducting 2H-MoS2 and MIS, serves as a solid state electron mediator in the heterostructure. Morphological findings revealed the growth of 1T/2H-MoS2 nanoflowers over MIS microflowers, verifying the close interaction between MIS and 1T/2H-MoS2. By virtue of accelerated e-/h+ pair separation and migration efficiency along with a proliferated density of active sites, the MMoS2-30 photocatalyst yields an optimum H2O2 of 35 μmol h-1 and H2 of 370 μmol h-1 (ACE of 5.9%), which is 3 and 2.7 fold higher than pristine MIS. This obvious enhancement can be attributed to photoluminescence and electrochemical aspects that substantiate the diminished charge transfer resistance along with improved charge carrier separation, representing a good example of a noble metal-free photocatalyst. The proposed Z-scheme charge transfer mechanism is aided by time-resolved photoluminescence (TRPL), XPS, radical trapping experiments, and EPR analysis. Overall, this endeavour provides advanced insights into the architecture of noble metal-free Z-scheme heterostructures, offering promising prospects in photocatalytic applications.

Directional Charge Pumping from Photoactive P-doped CdS to Catalytic Active Ni2 P via Funneled Bandgap and Bridged Interface for Greatly Enhanced Photocatalytic H2 Evolution

Loading cocatalysts onto semiconductors is one of the most popular strategies to inhibit charge recombination, but the efficiency is generally hindered by the localized built-in electric field and the weakly connected interface. Here, this work designs and synthesizes a 1D P-doped CdS nanowire/Ni2 P heterojunction with gradient doped P to address the challenges. In the composite, the gradient P doping not only creates a funneled bandgap structure with a built-in electric field oriented from the bulk of P-CdS to the surface, but also facilitates the formation of a tightly connected interface using the co-shared P element. Consequently, the photogenerated charge carriers are enabled to be pumped from inside to surface of the P-CdS and then smoothly across the interface to the Ni2 P. The as-obtained P-CdS/Ni2 P displays high visible-light-driven H2 evolution rate of ≈8265 µmol g-1 h-1 , which is 336 times and 120 times as that of CdS and P-CdS, respectively. This work is anticipated to inspire more research attention for designing new gradient-doped semiconductor/cocatalyst heterojunction photocatalysts with bridged interface for efficient solar energy conversion.

Transition Metal Phosphides (TMP) as a Versatile Class of Catalysts for the Hydrodeoxygenation Reaction (HDO) of Oil-Derived Compounds

Hydrodeoxygenation (HDO) reaction is a route with much to offer in the conversion and upgrading of bio-oils into fuels; the latter can potentially replace fossil fuels. The catalyst’s design and the feedstock play a critical role in the process metrics (activity, selectivity). Among the different classes of catalysts for the HDO reaction, the transition metal phosphides (TMP), e.g., binary (Ni2P, CoP, WP, MoP) and ternary Fe-Co-P, Fe-Ru-P, are chosen to be discussed in the present review article due to their chameleon type of structural and electronic features giving them superiority compared to the pure metals, apart from their cost advantage. Their active catalytic sites for the HDO reaction are discussed, while particular aspects of their structural, morphological, electronic, and bonding features are presented along with the corresponding characterization technique/tool. The HDO reaction is critically discussed for representative compounds on the TMP surfaces; model compounds from the lignin-derivatives, cellulose derivatives, and fatty acids, such as phenols and furans, are presented, and their reaction mechanisms are explained in terms of TMPs structure, stoichiometry, and reaction conditions. The deactivation of the TMP’s catalysts under HDO conditions is discussed. Insights of the HDO reaction from computational aspects over the TMPs are also presented. Future challenges and directions are proposed to understand the TMP-probe molecule interaction under HDO process conditions and advance the process to a mature level.

Atomically dispersed Pt inside MOFs for highly efficient photocatalytic hydrogen evolution

Pt is carried into the channels of UiO-66 with supercritical carbon dioxide to achieve high activity for hydrogen production by photolysis.

ZnIn2 S4 -Based Photocatalysts for Energy and Environmental Applications

As a fascinating visible-light-responsive photocatalyst, zinc indium sulfide (ZnIn₂ S₄ ) has attracted extensive interdisciplinary interest and is expected to become a new research hotspot in the near future, due to its nontoxicity, suitable band gap, high physicochemical stability and durability, ease of synthesis, and appealing catalytic activity. This review provides an overview on the recent advances in ZnIn₂ S₄ -based photocatalysts. First, the crystal structures and band structures of ZnIn₂ S₄ are briefly introduced. Then, various modulation strategies of ZnIn₂ S₄ are outlined for better photocatalytic performance, which includes morphology and structure engineering, vacancy engineering, doping engineering, hydrogenation engineering, and the construction of ZnIn₂ S₄ -based composites. Thereafter, the potential applications in the energy and environmental area of ZnIn₂ S₄ -based photocatalysts are summarized. Finally, some personal perspectives about the promises and prospects of this emerging material are provided.

Unique hierarchical SiO2@ZnIn2S4 marigold flower like nanoheterostructure for solar hydrogen production

The novel marigold flower like SiO2@ZnIn2S4 nano-heterostructure was fabricated using an in situ hydrothermal method. The nanoheterostructure exhibits hexagonal structure with marigold flower like morphology. The porous marigold flower assembly was constructed using ultrathin nanosheets. Interestingly, the thickness of the nanopetal was observed to be 5-10 nm and tiny SiO2 nanoparticles (5-7 nm) are decorated on the surface of the nanopetals. As the concentration of SiO2 increases the deposition of SiO2 nanoparticles on ZnIn2S4 nanopetals increases in the form of clusters. The optical study revealed that the band gap lies in the visible range of the solar spectrum. Using X-ray photoelectron spectroscopy (XPS), the chemical structure and valence states of the as-synthesized SiO2@ZnIn2S4 nano-heterostructure were confirmed. The photocatalytic activities of the hierarchical SiO2@ZnIn2S4 nano-heterostructure for hydrogen evolution from H2S under natural sunlight have been investigated with regard to the band structure in the visible region. The 0.75% SiO2@ZnIn2S4 showed a higher photocatalytic activity (6730 μmol-1 h-1 g-1) for hydrogen production which is almost double that of pristine ZnIn2S4. Similarly, the hydrogen production from water splitting was observed to be 730 μmol-1 h-1 g-1. The enhanced photocatalytic activity is attributed to the inhibition of charge carrier separation owing to the hierarchical morphology, heterojunction and crystallinity of the SiO2@ZnIn2S4.

Recent Progress of Transition Metal Phosphides for Photocatalytic Hydrogen Evolution

Photocatalytic hydrogen evolution can effectively alleviate the troublesome global energy crisis by converting solar energy into the chemical energy of hydrogen. In order to realize efficient hydrogen generation, a variety of semiconductor materials have been extensively investigated, including TiO₂ , CdS, g-C₃ N₄ , metal-organic frameworks (MOFs), and others. In recent years, to achieve higher photocatalytic performance and reach the level of large-scale industrial applications, photocatalysts decorated with transition metal phosphides (TMPs) have shone brightly because of their low cost, stable physical and chemical properties, and substitution for precious metals of TMPs. This Review highlights the preparation methods and properties associated with photocatalysis of TMPs. Moreover, the H₂ generation efficiency of photocatalysts loaded with TMPs and the roles of TMPs in catalytic systems are also studied systematically. Apart from being co-catalysts, several TMPs can also serve as host catalysts to boost the activity of photocatalytic composites. Finally, the development prospects and challenges of TMPs are put forward, which is valuable for future researchers to expand the application of TMPs in photocatalytic directions and to develop more active photocatalytic systems.

Electrospinning metal Phosphide/Carbon nanofibers from Phytic Acid for hydrogen evolution reaction catalysts

This paper reports a general electrospinning method to prepare various metal phosphide/carbon nanofibers composite for electrochemical hydrogen evolution reaction (HER) catalysts. An earth-abundant organic acid-phytic acid is successfully incorporated into a conventional electrospinning precursor as the phosphorus source, and continuous nanofibers can be obtained through spinning. After heat treatment, metal phosphide/carbon composite nanofibers can be obtained, with fine phosphide nanoparticles well dispersed on the surface of an interconnected carbon backbone network. Such fibrous structures offer fast charge transfer pathways and enlarged active surface area, which are beneficial for electrocatalysts. As a result, enhance HER catalytic activity can be achieved.

Simultaneous manipulation of ion doping and cocatalyst loading into Mn0.3Cd0.7S nanorods toward significantly improved H2 evolution

Ni₂P and Ni²⁺ jointly modified Mn_0.3Cd_0.7S photocatalysts were successfully fabricated via a facile solvothermal method. The loading of Ni₂P and the doping of Ni²⁺ proceeded simultaneously via a one-step process.

Regulation of the rutile/anatase TiO2 heterophase interface by Ni12P5 to improve photocatalytic hydrogen evolution

Loading Ni₁₂P₅ on an anatase/rutile surface reduces its photocatalytic activity, while embedding Ni₁₂P₅ within its junction interface enhances its photocatalytic activity.