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

Abstract

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.