Multielement-Doped Tungstic Acids via Submerged Photosynthesis for Enhanced All-Solar Photoelectrochemical Responses

Bifunctional electrode materials that can convert solar energy into electricity and store chemical energy are a functional strategy for resolving the instability of solar energy. However, most commonly used transition metal oxide semiconductor materials lack broadband wavelength absorption responses, resulting in incomplete solar energy utilization. Herein, multielement-doped Mo_xW_1-xO₃·0.33H₂O nanoparticles synthesized via the one-pot submerged photosynthesis of crystallite (SPsC) method are proposed to improve the full-spectrum solar responses of tungstic acids. The solar absorption efficiency of Mo_xW_1-xO₃·0.33H₂O increases from 54 to 81% after Cu, Fe, and Mn doping. This increase in the solar absorption efficiency of Mo_xW_1-xO₃·0.33H₂O improves its photogenerated capacitance by 18.7 times, which is attributed to the increase in the number of photogenerated charge carriers and planar defect structures produced via multielement doping. Moreover, ab initio calculations theoretically explain the relation between the elemental doping and corresponding absorption wavelengths of Mo_xW_1-xO₃·0.33H₂O, providing instructions for tuning the light absorption wavelength of transition metal oxide semiconductor materials. Multielement doping achieved via the low-cost SPsC method enhances the photocarrier response to increase the photogenerated capacitance. This response demonstrates the importance of full-spectrum solar absorption, offering a prominent strategy for designing solar energy storage materials in the future.