| Developing highly active and stable photocatalysts are crucial for achieving efficient light-driven hydrogen production.Cd-based sulfide photocatalysts,with narrow band gaps,suitable band edge position and adjustable surface electronic structure,have been widely used for photocatalytic H2 production under visible light.However,their photocatalytic activity and stability remain to be restricted due to the fast recombination of photogenerated charge carriers,sluggish surface reaction kinetics and photocorrosion.This paper employs strategies,such as constructing dynamic hydrogen evolution active sites via metal single-atom modification,achieving ultra-fast hydrogen migration pathways and oxygen evolution by inducing element doping on twinning surfaces,enhancing heterojunction bonding with cyanide groups,to accelerate charge separation and migration and reduce reaction energy barriers,resulting in efficient hydrogen evolution.The main research contents of this paper are summarized as followings:(1)The Ni-doped and Ni0-anchored atoms on the surface of CdS regulate the electronic structure and construct the dynamic catalytic sites for efficient photocatalytic hydrogen production:a unique NixCd1-xS-Ni0 photocatalyst,including the surface Ni doping and atomic Ni0 anchoring sites,is successfully prepared by Ni2+ions exchange reaction and in-situ photo-induction of Ni0,respectively.The surface Ni atoms effectively tune the electronic structure of neighboring S atoms,enhancing both H*adsorption-free energy and photocatalytic hydrogen evolution activity at S sites.Besides,photogenerated Ni0 atoms,anchored on unsaturated S atoms,serve as charge transfer bridges to reduce Ni2+ions in the solution to Ni clusters.Subsequently,the displacement reaction of Ni clusters with H+spontaneously proceeds to produce H2 in an aqueous solution of lactic acid.The equilibrium of photo-deposition/dissolution of Ni clusters realizes the construction of dynamic active sites,providing sustainable reaction centers and enhancing surface redox kinetics.(2)The surface Co atoms of twinned Co0.01Mn0.29Cd0.7S induces rapid H*migration pathways and fast oxygen evolution for efficient photocatalytic overall water splitting.The efficient Co0.01Mn0.29Cd0.7S photocatalyst was prepared by modifying the unsaturated Co atoms on the twinning Mn0.3Cd0.7S surface through a solvothermal method.The Co atoms regulate the electronic structure of neighboring S atoms to form an ultrafast H*migration channel,which promotes the capture of H*by the cubic-phase S sites in the water dissociation region,while accelerates the H*migration to the hexagonal-phase S sites and releases H2.Meanwhile,unsaturated Co atoms on the cubic phase as oxygen evolution reaction(OER)sites promote water deprotonation and optimize the kinetics of the rate-determining step to form OOH*intermediate,enhancing water oxidation activity.Co atoms with high spin-polarized states strengthen the internal electric field of the homojunction and local polarized electric field,inhibiting the bulk and surface recombination of photogenerated charge.(3)The construction of Eu-modified rich cyanide-group g-C3N4/twin MnCdS dual Z-scheme heterojunctions and interface charge regulation for efficient photocatalytic overall water splitting:Eu-modified rich cyanide-group g-C3N4 small nanosheets(CNNEu)were prepared using NaCl as a template and cutting action,and then CNNEu was hydrothermally stripped and in situ grown with twin MnCdS(MCS)to prepare CNNEu/MCS dual Z-type photocatalyst.Due to the coordinating effects of the cyanide group and lattice matching,the CNNEu/MCS photocatalyst exhibits a tightly contacted dual Z-type interface(CNNEu/hexagonal phase MCS/cubic phase MCS),which possesses the rapid charge transfer and strong water redox ability.During the catalytic reaction,photo-generated electrons migrate to the active Eu atoms on CNNEu for proton reduction,while holes quickly transfer to Mn atoms on cubic-phase MCS to participate in oxygen generation. |
PDF Full Text Request