A General Route to Prepare Low-Ruthenium-Content Bimetallic Electrocatalysts for pH-Universal Hydrogen Evolution Reaction by Using Carbon Quantum Dots.

ABSTRACT

A challenging but pressing task to design and synthesize novel, efficient, and robust pH-universal hydrogen evolution reaction (HER) electrocatalysts for scalable and sustainable hydrogen production through electrochemical water splitting. Herein, we report a facile method to prepare an efficient and robust Ru-M (M=Ni, Mn, Cu) bimetal nanoparticle and carbon quantum dot hybrid (RuM/CQDs) for pH-universal HER. The RuNi/CQDs catalysts exhibit outstanding HER performance at all pH levels. The unexpected low overpotentials of 13, 58, and 18 mV shown by RuNi/CQDs allow a current density of 10 mA cm-2 in 1 m KOH, 0.5 m H2 SO4 , and 1 m PBS, respectively, for Ru loading at 5.93 µgRu cm-2 . This performance is among the best catalytic activities reported for any platinum-free electrocatalyst. Theoretical studies reveal that Ni doping results in a moderate weakening of the hydrogen bonding energy of nearby surface Ru atoms, which plays a critical role in improving the HER activity.