Solar-driven production of hydrogen and acetaldehyde from ethanol on Ni-Cu bimetallic catalysts with solar-to-fuels conversion efficiency up to 3.8 %

Catalytic ethanol dehydrogenation is recognized as a promising approach to produce valuable chemical stocks, yet its industrialization suffers from high energy consumption. Here, we present an efficient solar-driven ethanol dehydrogenation process using a low-cost Ni-Cu bimetallic catalyst for the high-yield and selective production of H-2 and acetaldehyde. Under the irradiation of focused simulated solar light, 176.6 mmol g(catalyst)(-1) h(-1) of H-2 production rate with a high solar-to-fuel conversion efficiency (3.8 %) was achieved without additional thermal energy input, which is far more efficient than any previously reported photocatalytic ethanol dehydrogenation systems. Mechanistic investigations revealed that photothermal heating and hot carrier generation over Ni-Cu catalysts took responsibilities for the high activity. Hot electrons generated from Cu nanoparticles could migrate to Ni atoms, which simultaneously favored the separation of charge carriers and the activation of adsorbates. This study opens a promising pathway toward solar-energy conversion technology and advanced cost-effective industrial processes

Inhomogeneous RVO₄ Photocatalyst Systems (R = Y, Ce, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, Lu)

By resorting on first-principles dynamical simulations and supporting experiments, we present a systematic and detailed inspection of a new series of inhomogeneous photocatalytic RVO₄ systems (R = Y, Ce, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, Lu), where YVO₄ is the most representative member. We evidenced a carrier separation, promoted by Pt acting as a cocatalyst, which allows for a clear understanding of the electronic properties of these inhomogeneous systems. These, in turn, are shown to be of crucial importance in enhancing the photocatalytic activity in the cases of water or methanol aqueous solutions. The presence of f electrons, acknowledged as essential for an optimal photocatalytic performance, is clearly rationalized and the possibility of using Lu, in view of its smaller ionic radius, to enhance hydrogen generation is disclosed. Experiments confirm that YVO₄, GdVO₄, and LuVO₄ have a potentially much higher efficiency than compounds containing other rare earth lanthanides. Hence, we provide a comprehensive guideline for designing a new generation of photocatalysts possessing unprecedented efficiencies

The Role of Ni-Based Cocatalyst in Inhomogeneous RVO 4

International audienc

Inhomogeneous RVO 4

International audienc

Visible-Light-Mediated Methane Activation for Steam Methane Reforming under Mild Conditions: A Case Study of Rh/TiO₂ Catalysts

Hot-carrier-induced molecular activation over photoexcited metal nanostructures is an important research field in solar-to-chemical energy conversion. Here, we report that visible light-illuminated TiO₂-supported Rh nanoparticles could significantly enhance methane (CH₄) activation in steam methane reforming at mild operating temperature (below 300 °C) with an ∼50% decrease in apparent activation energy compared to that of the pure thermal process. Femtosecond time-resolved infrared spectroscopic measurement and density functional theory calculations show an ultrafast separation of hot carriers at the Rh-TiO₂ interface, resulting in the formation of an electron-deficient state of Rh^δ+ at the surface for successive CH₄ activation at low temperatures. Wavelength-dependent activities and kinetic isotope experiments validate that the photoexcited hot carriers in the Rh nanoparticles play a critical role in facilitating the rate-determining steps, i.e., the cleavage of the C–H bond in CH₄. This study opens a promising pathway toward C–H bond activation chemistry by the construction of active nanometal photocatalysts

Intermolecular cascaded pi-conjugation channels for electron delivery powering CO2 photoreduction

Photoreduction of CO2 to fuels offers a promising strategy for managing the global carbon balance using renewable solar energy. But the decisive process of oriented photogenerated electron delivery presents a considerable challenge. Here, we report the construction of intermolecular cascaded pi-conjugation channels for powering CO2 photoreduction by modifying both intramolecular and intermolecular conjugation of conjugated polymers (CPs). This coordination of dual conjugation is firstly proved by theoretical calculations and transient spectroscopies, showcasing alkynyl-removed CPs blocking the delocalization of electrons and in turn delivering the localized electrons through the intermolecular cascaded channels to active sites. Therefore, the optimized CPs (N-CP-D) exhibiting CO evolution activity of 2247 mu mol g(-1) h(-1) and revealing a remarkable enhancement of 138-times compared to unmodified CPs (N-CP-A). While conversion of CO2 to fuels may offer a bio-inspired means to renewably utilize fossil fuel emission, most materials demonstrate poor activities for CO2 reduction. Here, authors construct conjugated polymers that modulate photo-induced electron transfer to CO2 reduction catalysts