Coupling 0D and 1D Carbons for Electrochemical Hydrogen Production Promoted by Percolation Mechanism.

Developing hydrogen evolution reaction (HER) electrocatalysts with high activity, durability and moderate price are essential for sustainable hydrogen energy utilization. Here, we demonstrate the facile coupling of carbon dots (CDs, zero-dimensional carbon materials) and carbon fibres (CFs, one-dimensional carbon materials) for enhanced electrochemical hydrogen production. Electrochemical tests reveal that the CD/CF catalysts show outstanding catalytic activity with a small overpotential of 280 mV at the current density of 10 mA•cm-2, a small Tafel slope of 87 mV•dec-1 and prominent durability. Percolation theory is for the first time introduced to interpret the catalytic mechanism of the CD/CF catalysts. The special morphology assembled by the 0D carbons constitutes the percolating clusters and promote electron transport throughout the 1D carbons. The strategy and theory can be adapted to general electrocatalytic applications for achieving and interpreting precise tuning on highly efficient electron transfer in electrocatalysts.