MOF‐on‐MOF Heterostructured Electrocatalysts for Efficient Nitrate Reduction to Ammonia
Yingying Zou, Yuechen Yan, Qingsong Xue, Chaoqi Zhang, Tong Bao, Xinchan Zhang, Ling Yuan, Sicong Qiao, Li Song, Jin Zou, Chengzhong Yu, Chengzhong Yu, Chao Liu
Abstract
Abstract Electrocatalytic nitrate reduction reaction (NO 3 − RR) is an important route for sustainable NH 3 synthesis and environmental remediation. Metal–organic frameworks (MOFs) are one family of promising NO 3 − RR electrocatalysts, however, there is plenty of room to improve in their performance, calling for new design principles. Herein, a MOF‐on‐MOF heterostructured electrocatalyst with interfacial dual active sites and build‐in electric field is fabricated for efficient NO 3 − RR to NH 3 production. By growing Co‐HHTP (HHTP=2,3,6,7,10,11‐hexahydroxytriphenylene) nanorods on Ni‐BDC (BDC=1,4‐benzenedicarboxylate) nanosheets, experimental and theoretical investigations demonstrate the formation of Ni−O−Co bonds at the interface of MOF‐on‐MOF heterostructure, leading to dual active sites tailed for NO 3 − RR. The Ni sites facilitate the adsorption and activation of NO 3 − , while the Co sites boost the H 2 O decomposition to supply active hydrogen (H ads ) for N‐containing intermediates hydrogenation on adjacent Ni sites, cooperatively reducing the energy barriers of NO 3 − RR process. Together with the accelerated electron transfer enabled by built‐in electric field, remarkable NO 3 − RR performance is achieved with an NH 3 yield rate of 11.46 mg h −1 cm −2 and a Faradaic efficiency of 98.4 %, outperforming most reported MOF‐based electrocatalysts. This work provides new insights into the design of high‐performance NO 3 − RR electrocatalysts.