Mei Lei,Wei Wu,Lingling Sun,Qingyong Tian,Changzhong Jiang,Xiangheng Xiao
According to relative energy band positions between noble metals of Au, Ag, and wide bandgap semiconductor SnO 2 , Au, and Ag nanoparticles (NPs) modified hollow SnO 2 NPs were designed. Firstly, the hollow SnO 2 NPs have been synthesized by employing the silica template-assisted hydrothermal methods, then Au and Ag were coated on the surface of SnO 2 to form the core–shell structures, respectively. The morphology, composition, and optical properties of as-prepared samples have been investigated by various analytic methods. Subsequently, the photocatalytic reaction to Rhodamine B (RhB) dye under simulated-sunlight irradiation was employed to investigate their photocatalytic performance, the results demonstrate the metal–semiconductor with direct Schottky contact exhibited remarkable photocatalytic activity . The finite difference time domain (FDTD) calculation results illustrate the introduced and decorated Au and Ag NPs could enhance the harvesting abilities for visible light. We envision the aforementioned synthesized strategy and catalytic results are used to the designing and application of other metal–semiconductor system.
Dong Zhang,Dafeng Zhang,Dong Fan,Junchang Liu,Hengshuai Li,Xipeng Pu,Haiquan Hu,Feng Guo,Peiqing Cai
Photocatalytic hydrogen production technology has emerged as one of the most promising technologies to address the future energy crisis. Cd0.9Zn0.1S (CZS) is a promising photocatalyst for visible light activation but is limited by the slow kinetics of photoexcited carrier separation. Density functional theory (DFT) calculations based on first-principles showed that the introduction of a cocatalyst, N-doped graphite carbon (FC@NC), could effectively reduce the adsorption free energy of hydrogen, thus accelerating the hydrogen reaction kinetics of CZS. Supported by theoretical predictions, magnetic FC@NC nanoparticles were successfully prepared by precipitation and calcination and then combined with tetrapod CZS by ultrasonic self-assembly and calcination to form the FC@NC/CZS composite photocatalyst with Schottky contact. The FC@NC/CZS composite photocatalyst with the best mass ratio of FC@NC proved a considerable photocatalytic hydrogen evolution rate up to 79.9 ± 0.1 mmol g–1 h–1 under visible light exposure, which was 4.4 ± 0.1 times that of pristine CZS, and the apparent quantum efficiency (AQE) at 450 nm was as high as 52%. Finally, based on the experimental results and DFT calculations, a possible mechanism for the enhanced photocatalytic activity of FC@NC/CZS composites with the Schottky heterojunction was first proposed. In general, we attribute the boosted and stable photocatalytic property of FC@NC/CZS photocatalytic performance to the following three aspects: (1) the bimetallic alloy cocatalyst easily acts as an electron collector, (2) the graphite carbon layer protects the alloy from oxidation, and (3) the nitrogen-doped carbon layer provides more active sites for the reaction. This work provided a green and economical technique for an efficient hydrogen evolution reaction using light energy in the environment.
Continuous real-time human motion and heart-rate monitoring systems can provide vital clinical information for disease diagnosis, preventive healthcare and rehabilitation care. However, it is still a challenge to design wearable pressure/strain sensors with great flexibility and sustainable power for motion detection and physiological signal monitoring. Here, a self-powered laminated fabric sensor based on Schottky contact was successfully fabricated. This laminated fabric sensor was constructed by sandwiching the polypyrrole (PPy)-coated fabric with the Ni-coated fabric and Al plastic film. The electrical outputs under strain were attributed to the single Schottky contact between PPy and Al. This fabric sensor exhibited excellent stability under continuous quick cycling operation and at high relative humidity, which could be adapted to different human body parts for continuous motion detection and heart-rate monitoring. This work is of great significance to demonstrate a promising strategy toward self-powered wearable pressure sensors used for human motion detecting and hear-rate monitoring.
危险品化学品经营许可证（带存储）