Haoqiang Feng,Yike Li,Xian Liu,Kang Wang,Qianhao Du,Yingju Wang,Zhongjun Li
Developing efficient piezo-photocatalysts through integrating cation vacancies with double metal single atoms is vitally important for hydrogen production, while it remains a challenge. In this work, cadmium vacancy (V Cd ) as well as Pt and Pd single atoms (Pt-Pd) were simultaneously introduced into CdS to construct V Cd -CdS/Pt-Pd catalysts for piezo-photocatalytic hydrogen evolution. In-depth characterizations and DFT calculations confirmed that the symmetry breaking caused by V Cd , Pt-Pd dual single atoms and ultrasonic could induce the polarization enhancement and charge asymmetric distribution, modulate the density of electronic states as well as optimize the adsorption of H* intermediates. Under light and ultrasound, the optimal V Cd -CdS/Pt 0.20 -Pd 0.30 achieved the piezo-photocatalytic hydrogen evolution rate of 104.4 mmol g −1 h −1 , which was 10.0 and 30.7 times that of V Cd -CdS and CdS, respectively. The significant improvement of piezo-photocatalytic performance was due to the synergistic interaction of V Cd -CdS, Pt-Pd double single atoms and the ultrasonic-induced external stress, which enhanced the polarized electric field in V Cd -CdS/Pt-Pd and promoted the separation and transfer of photo-generated charges. Moreover, the piezoelectric polarization induced by ultrasonic could tilt the energy band and produce a stronger reduction potential, also facilitating the hydrogen evolution reaction. On the whole, the symmetry breaking achieved by structure modifications coupled with external stress effectively boosted the piezo-photocatalytic hydrogen evolution performance, which provided a reference for the design of high-efficiency piezo-photocatalysts based on vacancy engineering and double single atoms doping.
Wenhao Shi,Xitang Qian,Chuankai Zou,Meng Zhang,Chenhui Huang,Xiangshui Miao,Lei Ye
Ion transport is a critical phenomenon underpinning numerous biological, physical, and chemical systems. Proton transistors leveraging proton transport face significant limitations, such as a low on–off ratio and deficient carrier mobility, which restrict their applicability in biological and other scenarios. This study explores the use of two-dimensional (2D) vacancy-residing transition metal phosphorus trichallcogenide-based membranes as the active layer for proton field-effect transistors. The synthesized Cd0.85PS3Li0.15H0.15 membrane exhibits a well-organized layered structure and high hydrophilicity, with nanometer-sized interlayers containing interconnected water networks. These distinct features facilitate proton conduction, leading to a high proton conductivity value of 0.83 S cm–1 at 98% relative humidity and 90 °C, with an activation energy of 0.26 eV. The Cd0.85PS3Li0.15H0.15-based proton transistor demonstrates tunability via gate voltage, thereby enabling effective modulation of proton flow across source and drain electrodes. The transistor notably showcases superior switching characteristics, with an on/off ratio surpassing 5.51 and a carrier mobility of 8.84 × 10–2 cm2 V–1 s–1. The underlying mechanism for this performance enhancement is attributed to electric-field-induced switching in Cd vacancies. This research boosts the development of highly versatile ionotropic devices by introducing advanced 2D ion-conductive membranes.
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