纳米晶Pd修饰p-Si电极的制备及其光电析氢性能

在半导体p型Si上化学沉积金属Pd，制备了纳米晶Pd修饰p-Si电极.控制化学沉积的时间，可得到不同沉积量和不同尺度的Pd颗粒，沉积时间为20 min时，Pd颗粒的直径约为80 nm.XRD测试结果表明，Pd颗粒的平均晶粒尺寸为7.37 nm.重点研究了Pd/p-Si电极在光照前后的催化析氢性能.光照下Pd/p-Si电极的析氢过电位较无光照减小约250 mV，比半导体Si减小约450 mV（电流密度为2.5 mA•cm^-2时）.电化学交流阻抗谱（EIS）表明，光照下Pd/p-Si电极的电化学析氢反应电阻由未光照的593.12 Ω•cm2降低至442.20Ω•cm²，光照下的析氢反应速率明显增加.

Preparation of nanocrystalline Pd modified p-Si electrode and its hydrogen evolution property under illumination

Nanocrystalline Pd modified p-Si electrode (Pd/p-Si) was prepared by electroless deposition on p-Si. The structure and morphology were determined by XRD and SEM respectively. The results showed that the structure of Pd coatings was nanocrystalline and Pd particles with different sizes were obtained by controlling time.The average diameter of Pd particles was about 80 nm at deposition time of 20 min. The catalytic properties of the Pd/p-Si electrode for hydrogen evolution under illumination and in darkness were studied with the constant current polarization method. The results showed that the hydrogen evolution reaction (HER) potential of the Pd/p-Si electrode under illumination was 250 mV lower than that in darkness, and was 450 mV lower than that of p-Si electrode in darkness at current density of 2.5 mA•cm^-2. The results of electrochemistry A.C. impedance spectra (EIS) indicated that the electrochemistry HER resistance of the Pd/p-Si electrode decreased from 593.12 Ω•cm² to 442.20 Ω•cm² under illumination，and its HER rate increased evidently.