The scalable production of hydrogen could conveniently be realized by alkaline water electrolysis. Currently, the major challenge confronting hydrogen evolution reaction (HER) is lacking inexpensive alternatives to platinum-based electrocatalysts. Here we report a high-efficient and stable electrocatalyst composed of ruthenium and cobalt bimetallic nanoalloy encapsulated in nitrogen-doped graphene layers. The catalysts display remarkable performance with low overpotentials of only 28 and 218 mV at 10 and 100 mA cm⁻², respectively, and excellent stability of 10,000 cycles. Ruthenium is the cheapest platinum-group metal and its amount in the catalyst is only 3.58 wt.%, showing the catalyst high activity at a very competitive price. Density functional theory calculations reveal that the introduction of ruthenium atoms into cobalt core can improve the efficiency of electron transfer from alloy core to graphene shell, beneficial for enhancing carbon–hydrogen bond, thereby lowing ΔG_H* of HER.

Graphene has attracted increasing attention in different scientific fields including catalysis. Via modification with foreign metal-free elements such as nitrogen, its unique electronic and spin structure can be changed and these doped graphene sheets have been successfully employed in some catalytic reactions recently, showing them to be promising catalysts for a wide range of reactions. In this review, we summarize the recent advancements of these new and interesting catalysts, with an emphasis on the universal origin of their catalytic mechanisms. We are full of hope for future developments, such as more precisely controlled doping methods, atom-scale surface characterization technology, generating more active catalysts via doping, and finding wide applications in many different fields.

An FeCo alloy covered with nitrogen doped graphene is prepared by direct annealing of Fe₃[Co(CN)₆]₂nanoparticles, exhibiting efficient HER catalysis.

The metal-free catalytic reduction of 4-nitrophenol (Nip) to 4-aminophenol (Amp) mediated by N-doped graphene (NG) was reported. Nip could be reduced to Amp completely without any by-product generation. The activity of the NG is comparable with some of the previously reported metallic catalysts. Interestingly, the NG sheet catalyzed reaction follows pseudo-zero-order kinetics, while all the metallic catalysts follow pseudo-first-order kinetics. The in situ FTIR experiment demonstrated that Nip ions will combine with NG via the O atoms of their hydroxyl groups. Theoretical calculations verified this adsorption model, and confirmed that the adsorption of Nip ions is the critical step, leading to the pseudo-zero-order kinetics. Moreover, only the carbon atoms next to the doped N atoms on NG surface can be activated, serving as the active sites. As expected, all four kinds of the doped N atoms are beneficial to the adsorption and activation of Nip, contributing to the catalytic reduction reaction.