Abstract:
As an important clean energy carrier with a high combustion heat value, hydrogen is of great importance for addressing the challenges caused by an increasingly severe energy shortage and environmental pollution. Compared with traditional hydrogen production from fossil fuel (e.g. natural gas, coal) by steam reforming, the electrocatalytic production of hydrogen by water splitting is a renewable and eco-friendly technique. Currently, the widely used catalyst for the hydrogen evolution reaction (HER) is a noble metal (e.g. Pt), which has very limited availability and a high cost. Therefore, it is crucial to develop low-cost and highly effective alternative HER electrocatalysts. In this review, we summarize the use of carbon materials for noble metal-free HER catalysts, in which they play roles including as an active catalyst and a matrix component. By heteroatom doping, the intrinsic activities of carbon materials are optimized and improved, and carbon-based metal-free catalysts are produced. As a matrix, the main roles of the carbon materials are as conductive substrates, highly-dispersed support materials and corrosion resistant layers. The catalytic activity of carbon-based catalysts is improved by a synergistic effect between a co-catalyst and the carbon skeleton. The HER performance of some reported carbon-based catalysts are even close to that of Pt. We summarize the strategies for tailoring the HER performance of carbon-based electrocatalysts and the prospects for future research on developing highly efficient and low-cost catalysts are discussed.