Inner Co Synergizing Outer Ru Supported on Carbon Nanotubes for Efficient pH-Universal Hydrogen Evolution Catalysis

Exploring highly active but inexpensive electrocatalysts for the hydrogen evolution reaction (HER) is of critical importance for hydrogen production from electrochemical water splitting. Herein, we report a multicomponent catalyst with exceptional activity and durability for HER, in which cobalt nanoparticles were in-situ confined inside bamboo-like carbon nanotubes (CNTs) while ultralow ruthenium loading (similar to 2.6 mu g per electrode area similar to cm(-2)) is uniformly deposited on their exterior walls (Co@CNTs vertical bar Ru). The atomic-scale structural investigations and theoretical calculations indicate that the confined inner Co and loaded outer Ru would induce charge redistribution and a synergistic electron coupling, not only optimizing the adsorption energy of H intermediates (Delta G(H*)) but also facilitating the electron/mass transfer. The as-developed Co@CNTs vertical bar Ru composite catalyst requires overpotentials of only 10, 32, and 63 mV to afford a current density of 10 mA cm(-2) in alkaline, acidic and neutral media, respectively, representing top-level catalytic activity among all reported HER catalysts. The current work may open a new insight into the rational design of carbon-supported metal catalysts for practical applications.

Automated summary

In this study, a highly active and durable multicomponent catalyst for the hydrogen evolution reaction (HER) was developed. The catalyst, consisting of cobalt nanoparticles confined inside bamboo-like carbon nanotubes (CNTs) and ultralow ruthenium loading on the exterior walls, exhibited exceptional HER activity. The atomic-scale structural investigations and theoretical calculations revealed that the confined inner cobalt and loaded outer ruthenium induced charge redistribution and synergistic electron coupling, optimizing the adsorption energy of H intermediates and facilitating electron/mass transfer. The results demonstrated that the Co@CNTs | Ru catalyst achieved top-level catalytic activity among all reported HER catalysts. This work provides new insights for the rational design of carbon-supported metal catalysts for practical applications.