Recent progress in the hybrids of transition metals/carbon for electrochemical water splitting

Nowadays, hybrids of transition metals/carbon (TM/carbon) have attracted worldwide attention as efficient electrocatalysts for overall water splitting. By virtue of their tunable chemical compositions and nanostructures, as well as synergistic effects of TMs and carbon, TM/carbon hybrids will play an essential role in the design and development of novel yet excellent electrocatalytic nanomaterials. As such, in this review, we summarize the recent progress in the design and synthesis of TM/carbon hybrids with sophisticated nanostructures and their application in overall water splitting. Our attention was focused on three important categories of TM/carbon hybrids, namely transition metal alloy (TMA)/carbon hybrids, transition metal sulfide (TMS)/carbon hybrids, and transition metal phosphide (TMP)/carbon hybrids. We close this article with the challenges and outlook on TM/carbon hybrids as efficient and low-cost electrocatalysts, thereby promoting the development of this important area.