3D interconnected porous Mo-doped WO3@CdS hierarchical hollow heterostructures for efficient photoelectrochemical nitrogen reduction to ammonia

Photo/electrochemical fixation of atmospheric nitrogen (N2) into valuable chemicals is a favorable strategy to utilize the abundant natural resources for efficient catalysis. It is extremely desirable to discover immensely active, durable, and selective catalysts for effective photoelectrochemical N2 fixation. Herein, low-cost, non-noble metal-based porous Mo-doped WO3@CdS hollow microspheres as hierarchical heterostructures were synthesized that can effectively catalyze and reduce the gaseous N2 into ammonia (NH3). High Faradaic efficiency (36.72%) and fast average ammonia yield rate (38.99 µg h−1 mgcat−1) were observed at −0.3 V vs. RHE in the neutral solution at ambient conditions. Mo-doping and interconnected porous heterostructures synergistically deliver sufficient catalytic sites for effective photoelectrocatalytic N2 reduction. Furthermore, density functional theory (DFT) calculations validate that the Mo-doping WO3 is advantageous to decrease the energy barrier for N2 activation and protonation. Therefore, this work demonstrates the rational construction of transition metals-based hierarchical hollow photoelectrocatalysts towards efficient artificial N2 fixation. [Display omitted] •Porous Mo-WO3@CdS hierarchical hollow microspheres heterostructures (HMHs) are synthesized in the present work.•Hierarchical hollow microstructures increase the active surface area and accessibility to active sites.•Strong absorbance of light due to hollow Mo-WO3 structures enhanced the light-harvesting capability and play a key role in the PEC N2 reduction.•The hierarchical heterostructures demonstrated enhanced photoelectrocatalytic activity towards high FE and NH3 yield.