Rh single atoms/clusters confined in metal sulfide/oxide nanotubes as advanced multifunctional catalysts for green and energy-saving hydrogen productions

In this work, smart strategies are conducted to design advanced multifunctional electrocatalysts: Co₃S₄/CoO_x heterostructured nanosheets-assembled nanotube arrays on 3D framework integrated with single Rh atoms and subnanometer clusters. The catalyst can reach current density of 10 mA cm⁻² at low overpotentials of 248.2, and 56.1 mV for oxygen evolution reaction, and hydrogen evolution reaction, respectively. The catalyst also shows very low potential of 1.32 V for urea oxidation reaction at 10 mA cm⁻². A water electrolyzer that achieves current density of 10 mA cm⁻² at small cell voltage of 1.45 V is prepared under action of the developed catalyst. We also conduct urea electrolysis assembled with the catalyst and find that the device requires a cell voltage of only 1.35 V to drive a current density of 10 mA cm⁻², proving the great potential of our catalyst for simultaneous energy-saving H₂ production and the treatment of urea-rich wastewater.