However, its STH efficiency is greatly plagued by its limited light absorption, poor charge transport, and sluggish water oxidation kinetics. [2] In this context, recent research has focused on overcoming these intrinsic issues, including N 2 or H 2 treatment for improved light harvesting, [3] heteroatom doping for increasing charge carrier densities and thus charge transport, [4] and oxygen evolution cocatalyst (OEC) loading for facilitating the reaction kinetics. [5] Despite the effectiveness of the above methods, a simple route to synchronously improve the three processes for enhanced PEC photoanode performance of photoanode is highly desirable. This has yet to be largely explored.The operation temperature has been proven to be exert a profound influence on the bandgap of semiconductors, hole diffusion length of photoanodes and electrocatalytic properties of OECs. [6] For example, the absorption band of semiconductor quantum dots was found to exhibit a red shift with increasing temperature. [7] Minority carrier hopping was activated within BVO photoanodes via a moderate temperature elevation of the electrolyte, resulting in efficient bulk charge separation. [8] Furthermore, the electrocatalytic performance of OECs could be greatly enhanced by magnetic heating in an external high-frequency alternating magnetic field. [9] Inspired by the above intriguing results, it The ability of photoanodes to simultaneously tailor light absorption, charge separation, and water oxidation processes represents an important endeavor toward highly efficient photoelectrochemical (PEC) water splitting. Here, a robust strategy is reported to render markedly improved PEC water splitting via sandwiching a photothermal Co 3 O 4 layer between a BiVO 4 photoanode film and an FeOOH/NiOOH electrocatalyst sheet. The deposited Co 3 O 4 layer manifests compelling photothermal effect upon near-infrared irradiation and raises the temperature of the photoanodes in situ, leading to extended light absorption, enhanced charge transfer, and accelerated water oxidation kinetics simultaneously. The judiciously designed NiOOH/ FeOOH/Co 3 O 4 /BiVO 4 photoanode renders a superior photocurrent density of 6.34 mA cm -2 at 1.23 V versus a reversible reference electrode (V RHE ) with outstanding applied bias photon-to-current efficiency of 2.72% at 0.6 V RHE . In addition to the metal oxide, a wide variety of metal sulfides, nitrides, and phosphides (e.g., CoS, CoN, and CoP) can be exploited as the heaters to yield high-performance BiVO 4 -based photoanodes. Apart from BiVO 4 , other metal oxides (e.g., Fe 2 O 3 and TiO 2 ) can also be covered by photothermal materials to impart significantly promoted water splitting. This simple yet general strategy provides a unique platform to capitalize on their photothermal characteristics to engineer high-performing energy conversion and storage materials and devices.
