Cl2 Production by Photocatalytic Oxidation of HCl over TiO2

A mixed-linker strategy in covalent organic frameworks for enhanced sunlight-driven photocatalytic oxidation activity and stability

We present a simple mixed-linker strategy to enhance the photocatalytic oxidation activity and stability of covalent organic framework semiconductors. The TpTfbPa-COF, featuring an unconventional reversed AA-stacking structure with both imine and ketoamine linkages, exhibits excellent structural stability and superior photocatalytic performance compared to the fully imine-linked TfbPa-COF and the fully ketoamine-linked TpPa-COF.

Enhanced HClO production from chloride by dual cocatalyst loaded WO3 under visible light

Photocatalytic production of HClO was improved more than twice by co-loading of Mn compared to the standard Pt/WO3.

Promoting Electrocatalytic Oxygen Evolution of Ultrasmall NiFe (Hydr)oxide Nanoparticles by Graphene-Support Effects

Although the activity of electrocatalysts towards oxygen evolution reaction (OER) has achieved considerable improvement by modulating the intrinsic electron structure, the role of supports to OER performance, often being reduced to enhancing the conductivity, is not fully explored. In this paper, a proof-of-concept study based on a series of hybrids of nickel iron (hydr)oxide nanoparticles (NiFeO NPs) and carbon supports with different oxidation level compared the motivation of supports for OER activity. The key to implementation lay in anchoring and growing of NiFeO NPs on the various carbon supports by electrostatic assembly and subsequent in-situ reduction. A series of experiments indicated that the strong coupling of metal ions and graphene oxide (GO) contributed to the formation of ultrasmall NiFeO NPs (≈2 nm) and the firm interaction between NiFeO NPs and GO, which in turn resulted in exposing more metal atoms, modulating local electron structure of active sites, and accelerating the charge-transfer ability. The OER activity of optimal NiFeO NPs anchored on rGO (NiFeO NPs/rGO) was significantly elevated, achieving an overpotential as small as 201 mV at 10 mA cm^-2 and a low Tafel slope of 68 mV dec^-1 , as well as remarkable stability. Such exciting capacity for catalyzing OER prevailed over the vast majority of previously reported transition-metal electrocatalysts, even superior to numerous noble metal-containing catalysts. The electrolyzer employing NiFeO NPs/rGO and commercial Pt/C for anode and cathode could be powered by a solar cell for efficient alkaline seawater splitting. This work opens up a universal and scalable way for further advancing the intrinsic activity of energy-related materials.

Intensification of Heterogeneous Photocatalytic Reactions Without Efficiency Losses: The Importance of Surface Catalysis

Advances in LED and photoreactor technology have brought semiconductor photocatalysis to the verge of feasibility of industrial application for the synthesis of value-added chemicals. However, the often observed efficiency losses under intensified illumination conditions still present a great challenge. This perspective discusses the origin of these efficiency losses and what needs to be done to prevent or counteract it and pave the way for efficient, intensified heterogeneous photocatalytic processes. The role of surface catalysis is particularly highlighted as one of the rate-limiting steps.

Graphic Abstract

Effect of Calcination Temperature on the Activation Performance and Reaction Mechanism of Ce-Mn-Ru/TiO2 Catalysts for Selective Catalytic Reduction of NO with NH3

In this study, anatase TiO₂-supported cerium, manganese, and ruthenium mixed oxides (CeO _x -MnO _x -RuO _x /TiO₂; CMRT catalysts) were synthesized at different calcination temperatures via conventional impregnation methods and used for selective catalytic reduction (SCR) of NO _x with NH₃. The effect of calcination temperature on the structure, redox properties, activation performance, surface-acidity properties, and catalytic properties of the CMRT catalysts was investigated. The results show that the CMRT catalyst calcined at 350 °C exhibits the most efficient low-temperature (<120 °C) denitration activity. Moreover, the selective catalytic oxidation (SCO) reaction of ammonia is intensified when the reaction temperature is >200 °C, which leads to a decrease in the N₂ selectivity of the CMRT catalysts and further results in an increase in the production of NO and N₂O byproducts. X-ray photoelectron spectroscopy and in situ diffuse reflectance infrared Fourier transform spectroscopy show that the CMRT catalyst calcined at 350 °C contains more Ce⁴⁺, Mn⁴⁺, Ru⁴⁺, and lattice oxygen, which greatly improve the catalyst's ability to activate NO that promotes the NH₃-SCR reaction. The Ru ⁿ⁺ sites of the CMRT catalyst calcined at 250 °C are the competitive adsorption sites of NO and NH₃ molecules, while those of the CMRT catalyst calcined at 350 and 450 °C are active sites. Both the Langmuir-Hinshelwood (L-H) mechanism and the Eley-Rideal (E-R) mechanism occur on the surface of the CMRT catalyst at the low reaction temperature (100 °C).