Converting N2 to NH3 is an extremely valuable process but a long‐standing challenge in chemistry. The crux is the choice of catalysts, where single atomic catalysts (SAC) are always pursued as the altar of atomic catalysts. In this paper, double atomic catalysts (DAC) of TM2‐C2N with SAC of TM‐C2N (TM = Cr, Mn, Fe, Co, and Ni) for nitrogen reduction reaction (NRR) are systematically compared. Unexpectedly, TM2‐C2N are more suitable than TM‐C2N as catalysts for NRR. Moreover, the Mn2‐C2N endows the highest catalytic activity with the lowest potential of −0.23 V versus RHE, which is the best among all reported calculation results for NRR under ambient conditions. As a result, a new way to design catalysts with DAC is provided.

SACs, DACs, and TACs, heterogeneous catalysts with the advantages of homogeneous catalysts, are ideal models for exploring catalytic mechanisms and further designing catalysts.

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Molybdenum disulfide (MoS2), a two-dimensional layered material, has attracted ever-growing interest as one of the most promising non-noble-metal electrocatalysts for the hydrogen evolution reaction (HER). However, its catalytic efficiency is far from that of the best-performing Pt-based catalysts due to insufficient active sites and poor conductivity. Herein, density functional theory (DFT) simulations indicate that the catalytic activity of MoS2 could be improved through synergistic effects between the graphene substrate and Ni atom adsorption. Following this result, we designed and synthesized dual-modified MoS2 nanosheets with nanoporous Ni and reduced graphite oxide, which show a low onset potential (85 mV), a small Tafel slope (71.3 mV dec–1), and a high cycling stability as HER catalysts. Both the DFT and experimental results demonstrate that the above superior performances are derived from a large number of edge active sites and fast electron transport. This study provides a comprehensive understanding of the HER activity of MoS2 and also a new strategy to design high-performance HER catalysts aided by DFT simulations.

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A new 2D MoC6 is discovered as a nitrogen reduction reaction electrocatalyst with a quite low potential of −0.54 V.

The development of low‐cost and high‐efficiency catalysts for both hydrogen evolution reaction (HER) and oxygen evolution reaction (OER) in alkaline electrolyte is still challenging. Herein, interfacial Co/CoMoN heterostructures supported on Ni foam (Co/CoMoN/NF) are constructed by thermal ammonolysis of CoMoOx. In 1.0 m KOH solution, Co/CoMoN/NF heterostructures exhibit excellent HER activity with an overpotential of 173 mV at 100 mA cm−2 and a Tafel slope of 68.9 mV dec−1. Density functional theory calculations indicate that the low valence state Co site acts as efficient water‐dissociation promoter, while CoMoN substrate has favorable hydrogen adsorption energy, leading to an enhanced HER activity. The Co/CoMoN/NF heterostructures also achieve high OER activity with an overpotential of 303 mV at 100 mA cm−2 and a Tafel slope of 56 mV dec−1. Using Co/CoMoN/NF heterostructures as the cathode and anode, the alkaline electrolyzer requires a low voltage of 1.56 V to reach the current density of 100 mA cm−2 along with superior long‐term durability. This study provides a new design strategy toward low‐cost and excellent catalysts for water splitting.