Peeling off the surface: Pt-decoration of WSe 2 nanoflakes results in exceptional photoelectrochemical HER activity  

作　　者：Peter S.Toth Gabor Szabo Gabor Bencsik Gergely F.Samu Krishnan Rajeshwar Csaba Janaky 

机构地区：[1]Department of Physical Chemistry and Materials Science,Interdisciplinary Excellence Center,University of Szeged,Szeged,Hungary [2]Department of Chemistry and Biochemistry,The University of Texas at Arlington,Arlington,Texas,USA

出　　处：《SusMat》2022年第6期749-760,共12页可持续发展材料（英文）

基　　金：The authors thank the European Research Council(ERC)under the European Union’s Horizon 2020 research and innovation programs(Grant Agreement No.716539);Flow Photo Chemproject(Grant Agreement ID:862453)for financial support.

摘　　要：Photoelectrochemical(PEC)hydrogen evolution reaction(HER)was studied on exfoliated,pristine and Pt-decorated tungsten diselenide(p-WSe_(2))nanoflake samples,using a previously developed microdroplet PEC microscopy approach.The WSe 2 nanoflakes had well-defined thicknesses as measured by atomic force microscopy,and the Pt nanoparticles(NPs)were deposited by a variable num-ber of atomic layer deposition(ALD)cycles.An exceptionally high photocurrent density of 49.6 mA cm^(−2)(under 220 mW cm^(−2) irradiation)and internal-photon-to-electron-conversion efficiency(∼90%at 550 nm)were demonstrated on these Pt-decorated WSe_(2)(WSe_(2)-Pt)photocathodes.The Pt NP loading and thickness of WSe_(2) nanoflakes(in the 24–235 nm range)were used to fine-tune their PEC activity for HER.We found similar charge transfer and surface recombination kinetics of pristine and WSe_(2)-Pt specimens(as assessed by intensity-modulated photocurrent spectroscopy),which indicated significant differences in their bulk properties.X-ray and ultraviolet photoelectron spectroscopies were performed to identify defect states and quantify the density of states around the valence band of WSe_(2).The elevated temperature of the ALD process and the evolving Pt NP phase conspired to passivate the sub-surface(i.e.,bulk)defects in the WSe_(2) nanoflakes,resulting in their vastly improved PEC performance.

关 键 词：atomic layer deposition defect migration density of states hydrogen evolution layered semiconductor photoelectrochemical kinetics 

分 类 号：TB383[一般工业技术—材料科学与工程]