Nb-based,perovskite-type oxynitrides ANb(O,N)3(A=Sr,Ba)have been significantly attractive semicon-ductor materials for photoelectrochemical(PEC)water splitting due to their absorption abilities of intensive-visible-light.However,PEC activities of these perovskites are relatively low due to reduction of Nb species during nitridation leading to the generation of anion defects and impurity phases.Herein,we propose nitridation of A-rich,layered perovskite A5Nb4O15 as starting oxides for general syn-thesis of photoactive ANbO2N.These layered perovskite A5Nb4O15 were completely transformed to single phase perovskite-type ANbO2N by nitridation.Wavelength onsets of light absorption were observed at 700 nm for SrNbO2N and at 740 nm for BaNbO2N.According to X-ray photoelectron spectroscopy results,excess Lewis base A species significantly suppressed the generation of reduced species such as Nb4+and Nb3+during nitridation,although it led to an amorphous surface of the as-prepared oxynitride.Subsequent annealing in Ar largely enhanced surface crystallinity of ANbO2N.As a result,Co(OH)x/ANbO2N/FTO photoanodes,prepared by loading Co(OH)x electrocatalyst,showed high photocurrent den-sity of 1.6(A=Sr)and 2.4 mA cm-2(A=Ba)at 1.23 VRHE under AM 1.5 G simulated sunlight.These results demonstrate that A-rich layered perovskite A5Nb4O15 are effective starting precursors for preparing low-defective ANbO2N.thus improving PEC water splitting activitv.

Sukanya Ramaraj;Jeongsuk Seo

Department of Chemistry,College of Natural Sciences,Chonnam National University,77 Yongbong-ro,Buk-gu,Gwangju 61186,Republic of Korea

能源化学

[1]Sukanya Ramaraj;Jeongsuk Seo-.Intensive-visible-light-responsive ANbO2N(A=Sr,Ba)synthesized from layered perovskite A5Nb4O15 for enhanced photoelectrochemical water splitting)[J].能源化学,2022(05):529-537

ANbO2N,A5Nb4O15,oxynitrides,ANb,SrNbO2N,BaNbO2N,Nb4+and,Nb3+during,oxynitride,activitv

Intensive,visible,responsive,synthesized,from,layered,enhanced,photoelectrochemical,water,splitting,type,have,been,significantly,attractive,semicon,ductor,materials,PEC,due,their,absorption,abilities,intensive,However,activities,these,perovskites,relatively,low,reduction,species,nitridation,leading,generation,anion,defects,impurity,phases,Herein,propose,rich,starting,oxides,general,thesis,photoactive,These,were,completely,transformed,single,by,Wavelength,onsets,observed,According,ray,photoelectron,spectroscopy,results,excess,Lewis,suppressed,reduced,such,although,led,amorphous,surface,prepared,Subsequent,annealing,Ar,largely,crystallinity,Co,FTO,photoanodes,loading,electrocatalyst,showed,high,photocurrent,den,sity,mA,VRHE,under,AM,simulated,sunlight,demonstrate,that,effective,precursors,preparing,defective,thus,improving

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