Active sites of two-dimensional(2D)electrocatalysts are often partially blocked owing to their inevitable stacking and hydrophobic polymeric binders in macroscale electrodes,therefore impeding their applications in ef...Active sites of two-dimensional(2D)electrocatalysts are often partially blocked owing to their inevitable stacking and hydrophobic polymeric binders in macroscale electrodes,therefore impeding their applications in efficient electrolyzers.Here,using layered double hydroxide(LDH)nanosheets as a model 2D electrocatalyst,we demonstrate that their performance toward water splitting can be boosted when they are electrostatically assembled into an organized structure pillared by hydrophilic polyelectrolytes or nanoparticles in a layer-by-layer(LbL)fashion.In particular,their mass activity on a planar electrode can be as large as 2.267 mA·μg^(-1) toward oxygen evolution reaction(OER),when NiFe-LDH nanosheets are electrostatically connected by poly(sodium 4-styrenesulfonate)(PSS),while drop-casted NiFe-LDH nanosheets only have a mass activity of 0.116 mA·μg^(-1).In addition,these homogeneous NiFe-LDH nanofilms can be easily deposited on three-dimensional(3D)surfaces with high areas,such as carbon cloths,to serve as practical electrodes with overpotentials of 328 mV at a current density of 100 mA·cm^(-2),and stability for 40 h.Furthermore,Pt nanoparticles can be LbL assembled with NiFe-LDH as bifunctional electrodes for synergistically boosted oxygen and hydrogen evolution reactions(HER),leading to successful overall water splitting powered by a 1.5 V battery.This study heralds the spatial control of 2D nanomaterials in nanoscale precision as an efficient strategy for the design of advanced electrocatalysts.展开更多
Recently discovered bismuth oxychalcogenide(Bi_(2) O_(2) Se) has aroused great interest due to its ultrahigh carrier mobility,tunable band gap and good environmental stability,making it a promising candidate for high-...Recently discovered bismuth oxychalcogenide(Bi_(2) O_(2) Se) has aroused great interest due to its ultrahigh carrier mobility,tunable band gap and good environmental stability,making it a promising candidate for high-performance electronics and optoelectronics.Their synthesis by colloidal approaches represents a cost-effective alternative to well-established chemical vapor deposition methods,and the resulting electronic-grade inks are important for large-area printed or wearable electronics.However,it is still challenging to control the colloidal growth of Bi_(2) O_(2) Se nanosheets in solution in addition to their assembly into high-performance thin films.Here,we report a two-step colloidal synthesis of Bi_(2) O_(2) Se nanosheets by separating the seeding and growth steps,thereby achieving controllable production of nanosheets with a lateral size of 1.4 mm and a thickness of 10 nm at optimized reaction conditions.These Bi_(2) O_(2) Se nanosheets are electrostatically assembled into large-area thin films,from which a photodetector is fabricated with a responsivity of 6.1 A/W and a short response time of 368 ms under the 520-nm laser illumination.The device exhibits fast response to modulations as high as 100 k Hz,along with a à3 dB bandwidth of 1 kHz.This work provides an important understanding of the controlled colloidal synthesis of Bi_(2) O_(2) Se nanosheets,and demonstrates their potential applications in fast photodetectors.展开更多
基金supported by the National Natural Science Foundation of China(NSFC)(Nos.52273076,52111540268,and 12004195)the 111 Project(No.B18030)in China+1 种基金The authors also acknowledge the financial support by Haihe Laboratory of Sustainable Chemical Transformations(No.YYJC202101)Open Research Fund Program of the State Key Laboratory of Low Dimensional Quantum Physics(No.KF202113).
文摘Active sites of two-dimensional(2D)electrocatalysts are often partially blocked owing to their inevitable stacking and hydrophobic polymeric binders in macroscale electrodes,therefore impeding their applications in efficient electrolyzers.Here,using layered double hydroxide(LDH)nanosheets as a model 2D electrocatalyst,we demonstrate that their performance toward water splitting can be boosted when they are electrostatically assembled into an organized structure pillared by hydrophilic polyelectrolytes or nanoparticles in a layer-by-layer(LbL)fashion.In particular,their mass activity on a planar electrode can be as large as 2.267 mA·μg^(-1) toward oxygen evolution reaction(OER),when NiFe-LDH nanosheets are electrostatically connected by poly(sodium 4-styrenesulfonate)(PSS),while drop-casted NiFe-LDH nanosheets only have a mass activity of 0.116 mA·μg^(-1).In addition,these homogeneous NiFe-LDH nanofilms can be easily deposited on three-dimensional(3D)surfaces with high areas,such as carbon cloths,to serve as practical electrodes with overpotentials of 328 mV at a current density of 100 mA·cm^(-2),and stability for 40 h.Furthermore,Pt nanoparticles can be LbL assembled with NiFe-LDH as bifunctional electrodes for synergistically boosted oxygen and hydrogen evolution reactions(HER),leading to successful overall water splitting powered by a 1.5 V battery.This study heralds the spatial control of 2D nanomaterials in nanoscale precision as an efficient strategy for the design of advanced electrocatalysts.
基金supported by National Science Foundations of China (Nos.51873088, 12004195)Natural Science Foundations of Tianjin (No.20JCQNJC01820)+2 种基金Tianjin Municipal Science and Technology Commission (No.18JCZDJC38400)“111” Project of China’s Higher Education (No.B18030)Fundamental Research Funds for the Central Universities from Nankai University (No.63201061)。
文摘Recently discovered bismuth oxychalcogenide(Bi_(2) O_(2) Se) has aroused great interest due to its ultrahigh carrier mobility,tunable band gap and good environmental stability,making it a promising candidate for high-performance electronics and optoelectronics.Their synthesis by colloidal approaches represents a cost-effective alternative to well-established chemical vapor deposition methods,and the resulting electronic-grade inks are important for large-area printed or wearable electronics.However,it is still challenging to control the colloidal growth of Bi_(2) O_(2) Se nanosheets in solution in addition to their assembly into high-performance thin films.Here,we report a two-step colloidal synthesis of Bi_(2) O_(2) Se nanosheets by separating the seeding and growth steps,thereby achieving controllable production of nanosheets with a lateral size of 1.4 mm and a thickness of 10 nm at optimized reaction conditions.These Bi_(2) O_(2) Se nanosheets are electrostatically assembled into large-area thin films,from which a photodetector is fabricated with a responsivity of 6.1 A/W and a short response time of 368 ms under the 520-nm laser illumination.The device exhibits fast response to modulations as high as 100 k Hz,along with a à3 dB bandwidth of 1 kHz.This work provides an important understanding of the controlled colloidal synthesis of Bi_(2) O_(2) Se nanosheets,and demonstrates their potential applications in fast photodetectors.