Recent progress of photocatalysts based on tungsten and related metals for nitrogen reduction to ammonia

Abstract

Photocatalytic nitrogen reduction reaction (NRR) to ammonia holds a great promise for substituting the traditional energy-intensive Haber–Bosch process, which entails sunlight as an inexhaustible resource and water as a hydrogen source under mild conditions. Remarkable progress has been achieved regarding the activation and solar conversion of N2 to NH3 with the rapid development of emerging photocatalysts, but it still suffers from low efficiency. A comprehensive review on photocatalysts covering tungsten and related metals as well as their broad ranges of alloys and compounds is lacking. This article aims to summarize recent advances in this regard, focusing on the strategies to enhance the photocatalytic performance of tungsten and related metal semiconductors for the NRR. The fundamentals of solar-to-NH3 photocatalysis, reaction pathways, and NH3 quantification methods are presented, and the concomitant challenges are also revealed. Finally, we cast insights into the future development of sustainable NH3 production, and highlight some potential directions for further research in this vibrant field.

Recent advances in polyoxometalate-based materials and their derivatives for electrocatalysis and energy storage

“…POMs can maintain high structural stability while rapidly gaining or losing electrons, which is conducive to improving the efficiency of multi-electron catalytic reactions. 57,58 (iv) Adjustable valence state. The same polyoxoanion can exist in both oxidized and reduced states, and undergo color changes during electron gain or loss, which is favorable to energy storage devices like lithium-ion batteries and pseudocapacitors where energy storage and release are based on chemical redox reactions.…”

“…In the NRR process, POMs can be defined as an electron reservoir to provide electrons directly to N 2 molecules, which is beneficial to the activation of N 2 molecules. 57,58 Besides, POMs have been proved by DFT calculations to be an electron source pointing to the active site in the NRR process. 57 Hence, POM-based materials can be used as an ideal candidate catalyst for the NRR in both experimental and theoretical studies.…”