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High Resolution Image Download MS PowerPoint Slide Electrocatalytic nitrate reduction to ammonia (eNRA) is a promising route toward environmental sustainability and clean energy. However, its efficiency is often limited by the slow conversion of intermediates due to spin-forbidden processes. Here, we introduce a novel A-site high-entropy strategy to develop a new perovskite oxide (La 0.2 Pr 0.2 Nd 0.2 Ba 0.2 Sr 0.2 )CoO 3-δ (LPNBSC) for eNRA. The LPNBSC possesses a higher concentration of high-spin (HS) cobalt-active centers, resulting from an increased concentration of CoO 5 structural motifs compared to conventional LaCoO 3 . Consequently, this material exhibits a significantly improved electrocatalytic performance toward ammonia (NH 3 ) production, resulting in a 3-fold increase in yield rate (129 μmol h –1 mg cat. –1 ) and a 2-fold increase in Faradaic efficiency (FE, 76%) compared to LaCoO 3 at the optimal potential. Furthermore, the LPNBSC-based Zn-nitrate battery reaches a maximum FE of 82% and an NH 3 yield rate of 57 μmol h –1 cm –2 . Density functional theory calculations reveal that A-site high-entropy management in perovskites facilitates nitrate activation and potentially optimizes the thermodynamic rate-determining step of the eNRA process, namely, *HNO 3 + H + + e – → *NO 2 + H 2 O. This work presents an efficient concept for modulating the spin state of the B-site metal in perovskites and offers valuable insights for the design of high-performance eNRA catalysts.
Guo et al. (Thu,) studied this question.