Intermolecular Metallic Single-Site Complexes Dispersed on Mo_2TiC_2T_x/MoS_2 Heterostructure Induce Boosted Solar-Driven Water Splitting

摘要

Successful development of an electrocatalyst capable to promote the hydrogenevolution reaction (HER) and the oxygen evolution reaction (OER) elements ofwater electrolysis is desirable for green hydrogen gas production. Herein,this work designs intermolecular metallic single-site complexes of ironphthalocyanine (Fe_(Pc)) and vanadium oxide phthalocyanine (VO_(Pc)) duallyimmobilized on 3D hierarchical MoS2-coated Mxene Mo2TiC2Tx (MX/MoS_2)heterostructures as a high-performance bifunctional electrocatalyst. The wellorganizedstructure with an unusual coordination environment and electroniclocalization impressively enhances water adsorption and activation to remarkablyaccelerate HER and OER kinetics. Therefore, the hybrid material requiresoverpotentials as small as 17.4 and 300 mV to drive 10 mA cm~（?2） for the HERand 50 mA cm~(?2) for the OER in 1.0 m KOH media, respectively. The electrolyzerof MX/MoS_2-FePcVOPc(+,?) exhibits low cell voltage of only 1.45 V to reacha current response of 10 mA cm~(?2) in 7.0 m KOH at 75 ℃ along with excellentcurrent retention stability of 99%/94% after long-term operations of 30 h at10/50 mA cm~（?2）. Moreover, a solar-to-hydrogen conversion efficacy of 19.96%is achieved in a solar energy-powered water electrolysis system, highlightingthe great potential of the developed MX/MoS2-FePcVOPc electrocatalysttoward water electrolysis.