Photocatalytic hydrogen evolution from pure water is successfully realized by using interstitial P-doped CdS with rich S vacancies (CdS-P) as the photocatalyst in the absence of any electron sacrificial agents. Through interstitial P doping, the impurity level of S vacancies is located near the Fermi level and becomes an effective electron trap level in CdS-P, which can change dynamic properties of photogenerated electrons and thus prolong their lifetimes. The long-lived photogenerated electrons are able to reach the surface active sites to initiate an efficient photocatalytic redox reaction. Moreover, the photocatalytic activity of CdS-P can be further improved through the loading of CoP as a cocatalyst.

No abstract

Black phosphorus (BP) has recently drawn attention in photocatalysis for its optical properties. However, limited by the rapid recombination of photogenerated carriers, the use of BP for photocatalytic water splitting still remains a huge challenge. Herein, we prepare a black/red phosphorus (BP/RP) hetero‐phase junction photocatalyst by a wet‐chemistry method to promote the interfacial charge separation and thus achieve Z‐scheme photocatalytic water splitting without using sacrificial agents. The Z‐scheme mechanism was confirmed by time‐resolved transient absorption spectroscopy. This work provides a novel insight into the interface design of hetero‐phase junction with atomic precision.

Metal halide perovskites with direct band gap and strong light absorption are promising materials for harvesting solar energy; however, their relatively narrow band gap limits their redox ability when used as a photocatalyst. Adding a second semiconductor component with the appropriate band structure offsets can generate a Z-scheme photocatalytic system, taking full advantage of the perovskite’s intrinsic properties. In this work, we develop a direct Z-scheme photocatalyst based on formamidinium lead bromide and bismuth tungstate (FAPbBr3/Bi2WO6) with strong redox ability for artificial solar-to-chemical energy conversion. With desirable band offsets and strong joint redox potential, the dual photocatalyst is shown to form a semicoherent heterointerface. Ultrafast transient infrared absorption studies employing selective excitation reveal synergetic photocarrier dynamics and demonstrate Z-scheme charge transfer mechanisms. Under simulated solar irradiation, a large driving force photoredox reaction (∼2.57 eV) of CO2 reduction coupled with benzyl alcohol oxidation to benzaldehyde is achieved on the Z-scheme FAPbBr3/Bi2WO6 photocatalyst, harnessing the full synergetic potential of the combined system.

Hot-carrier-induced molecular activation over photoexcited metal nanostructures is an important research field in solarto-chemical energy conversion. Here, we report that visible lightilluminated TiO 2 -supported Rh nanoparticles could significantly enhance methane (CH 4 ) 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-TiO 2 interface, resulting in the formation of an electron-deficient state of Rh δ+ at the surface for successive CH 4 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 CH 4 . This study opens a promising pathway toward C−H bond activation chemistry by the construction of active nanometal photocatalysts.

While the majority of the photochemical states and pathways related to the biological capture of solar energy are now well understood and provide paradigms for artificial device design, additional low-energy states have been discovered in many systems with obscure origins and significance. However, as low-energy states are naively expected to be critical to function, these observations pose important challenges. A review of known properties of low energy states covering eight photochemical systems, and options for their interpretation, are presented. A concerted experimental and theoretical research strategy is suggested and outlined, this being aimed at providing a fully comprehensive understanding.

Methanol synthesis via carbon dioxide (CO2) reduction is challenging and important because this technology can convert CO2 by solar-or wind-generated hydrogen into liquid fuel. The present work introduces the visible light as an external stimulus and for the first time demonstrates that methanol synthesis over Cu/ZnO catalysts can be effectively promoted by solar energy under atmospheric pressure.Experimental and theoretical studies document that hot electrons were photo-excited by localized surface plasmon resonance (LSPR) on Cu nanoparticles and such photo-excited hot electrons could transfer to ZnO through the metal-support interfaces.The hot electrons on Cu and ZnO synergistically facilitated the activation of reaction intermediates. Consequently, the activation energy was reduced by 40% and the methanol synthesis activity was promoted by 54%. This work provides a new strategy towards synthesis of liquid fuel via CO2 reduction under low pressure and sheds new light on the mechanism of photo-mediated catalysis.

Cu2O, a low‐cost, visible light responsive semiconductor photocatalyst represents an ideal candidate for visible light driven photocatalytic reduction of N2 to NH3 from the viewpoint of thermodynamics, but it remains unexplored. Reported here is the successful synthesis of uniformly sized and ultrafine Cu2O platelets, with a lateral size of <3 nm, by the in situ topotactic reduction of a CuII‐containing layered double hydroxide with ascorbic acid. The supported ultrafine Cu2O offered excellent performance and stability for the visible light driven photocatalytic reduction of N2 to NH3 (the Cu2O‐mass‐normalized rate as high as 4.10 mmol gCu2normalO −1 h−1 at λ>400 nm), with the origin of the high activity being long‐lived photoexcited electrons in trap states, an abundance of exposed active sites, and the underlying support structure. This work guides the future design of ultrafine catalysts for NH3 synthesis and other applications.