Piezopotential-driven simulated electrocatalytic nanosystem of ultrasmall MoC quantum dots encapsulated in ultrathin N-doped graphene vesicles for superhigh H2 production from pure water

Abstract

A simulated electrocatalytic nanosystem of MoC@NG assembled nanosheet is successfully constructed by a thermolysis procedure and first applied in piezocatalytic H 2 production from pure water. Owing to the unique configuration of MoC quantum dots (QDs) encapsulated in ultrathin N-doped graphene (NG) vesicles (MoC@NG), both the aggregation of MoC QDs and stack of ultrathin NG layers in MoC@NG are suppressed simultaneously. When the integration is subjected in mechanical vibration, ultrathin NG layers can provide piezoelectric potential to trigger hydrogen evolution reaction (HER) on MoC QDs, while MoC QDs could not only collect free electrons to achieve the carriers’ intercomponent separation, but also provide rich and high-activity HER sites with lower overpotential. The rate of piezocatalytic H 2 production from H 2 O is as high as 1.690 μmol h −1 mg −1 , which is the reported highest H 2 evolution rate of piezocatalytic water splitting without any sacrificial agents, even higher than ones in many photocatalytic pure water splitting systems. It is the synergy of piezoelectric ultrathin NG layers and conductive MoC QDs that predominantly contributes to a superhigh piezocatalytic performance. Furthermore, this design concept is expected to break a new ground in piezocatalysis. • MoC@NG is fabricated as a simulated electrocatalytic nanosystem. • MoC@NG has an unique configuration of ultrasmall MoC encapsulated in ultrathin NG. • MoC@NG is first applied in piezocatalytic H 2 evolution from pure H 2 O. • Ultrathin NG layers can provide piezoelectric potential to trigger HER on MoC QDs. • MoC@NG shows the reported highest H 2 evolution rate driven by piezopotential.