NH 3 synthesis by the electrocatalytic N 2 reduction reaction (NRR) under ambient conditions is an appealing alternative to the currently employed industrial method-the Haber-Boschp rocess-that requires high temperature and pressure.W er eport single Mo atoms anchored to nitrogendoped porous carbon as ac ost-effective catalyst for the NRR. Benefiting from the optimally high density of active sites and hierarchically porous carbon frameworks,t his catalyst achieves ah igh NH 3 yield rate (34.0 AE 3.6 mg NH 3 h À1 mg cat. À1 )a nd ahigh Faradaic efficiency (14.6 AE 1.6 %) in 0.1m KOHatroom temperature.T hese values are considerably higher compared to previously reported non-precious-metal electrocatalysts. Moreover,t his catalyst displays no obvious current drop during a5 0000 sN RR, and high activity and durability are achieved in 0.1m HCl. The findings provideapromising lead for the design of efficient and robust single-atom non-preciousmetal catalysts for the electrocatalytic NRR.

In situtransformation of Pd into β-PdH is the origin of the high selectivity for CO in the electrochemical CO2reduction reaction using Pd as the electrocatalyst.

The development of highly active and durable catalysts for electrochemical reduction of CO2 (ERC) to CH4 in aqueous media is an efficient and environmentally friendly solution to address global problems in energy and sustainability. In this work, an electrocatalyst consisting of single Zn atoms supported on microporous N-doped carbon was designed to enable multielectron transfer for catalyzing ERC to CH4 in 1 M KHCO3 solution. This catalyst exhibits a high Faradaic efficiency (FE) of 85%, a partial current density of −31.8 mA cm–2 at a potential of −1.8 V versus saturated calomel electrode, and remarkable stability, with neither an obvious current drop nor large FE fluctuation observed during 35 h of ERC, indicating a far superior performance than that of dominant Cu-based catalysts for ERC to CH4. Theoretical calculations reveal that single Zn atoms largely block CO generation and instead facilitate the production of CH4.