本研究係以氯化鋅及硫代硫酸鈉為前驅鹽，利用脈衝式電沉積法沉積ZnS於CdS/TiO2基材上來製備ZnS/CdS/TiO2光陽極，文中探討電沉積變因對所得光陽極組成及結構之影響，並進一步探討光陽極之光電化學活性及產氫速率之影響。
在電沉積ZnS實驗中，吾人改變施加電壓、電解液組成、pH值、沉積電量、溫度以及煅燒溫度來探討，並利用XRD、SEM、TEM、XPS及UV等儀器來進行特性分析。分析光陽極之活性時，利用Xe燈源（100 mW/cm2）照射光陽極，並以0.25 M Na2S、0.35 M Na2SO3水溶液作為電解液，進行光電化學反應，以評估各光陽極之光活性。最後利用雙槽式反應器進行產氫實驗，探討陽極攪拌速率及鹼液濃度對產氫速率之影響。
實驗結果發現，電沉積變因對ZnS之析出量、粒徑大小、缺陷及表面電荷影響甚鉅，進而影響光陽極之光活性。最適之製備條件：還原電壓為-0.8V（vs Ag/AgCl）、電解液組成為0.03 M ZnCl2、0.3 M Na2S2O3水溶液、pH值為3、沉積溫度25℃、施加1.0庫倫電量、鍛燒溫度350℃。此條件下所得光陽極光活性為最佳。
由產氫實驗中發現，最適攪拌轉速為300rpm、且最適之陽極液組成為1 M NaOH + 0.25 M Na2S + 0.35 M Na2SO3水溶液。此時光電流可達8.17 mA-cm-2，其對應之光轉換效率為3.56%，產氫速率為87.98 mol-cm-2-h-1，並且速率可長時間保持穩定；相較於為沉積ZnS之CdS/TiO2光陽極而言，光活性提昇，產氫速率亦增加，且可減少光陽極之光腐蝕性，而延長其使用壽命。

In this work, ZnS/CdS/TiO2 photoanodes were prepared by pulse electrodeposition from zinc chloride and sodium thiosulfate solutions. The influence of the electrodeposition condition on the composition and structure of photoanode was investgated. Furthermore, the photoelectrochemical activities and hydrogen production rates of the photoanodes were also studied.
For the study of ZnS electrodeposition, the preparation conditions including applied voltage, electrolyte composition, pH, input electricity, deposition temperature, and calcination temperature were investigated. The characterizations of photoanodes were investigated by means of XRD, SEM, TEM, XPS and UV techniques. In order to measure the photoactivity of prepared photoanode, a photoelectrochemical (PEC) cell with an electrolyte of 0.25 M Na2S and 0.35 M Na2SO3 were used under illumination by Xe lamp (100 mW/cm2). Moreover, the hydrogen generation experiment was carried out in a two-compartment PEC reactor. The concentration of alkaline electrolyte and the stirring rate in the anode compartment were investigated as well.
The results showed that deposition amount, particle size, defects, and surface charges of ZnS layer were strongly influenced by the deposition conditions, which would in advance manipulate the photoactivity of photoanode. It was found that the optimal deposition conditions were: reductive voltage of -0.8 V (vs. Ag/AgCl), the electrolyte of 0.03 M ZnCl2, 0.3 M Na2S2O3, pH3, input reductive electricity of 1 C, deposition temperature of 25 ℃ and calcination temperature of 300 ℃.
From the results of hydrogen genetation experiment, it revealed that the hydrogen generation condition was optimized at rotating speed of 300 rpm and the electrolyte of 1 M NaOH, 0.35 M Na2SO3 and 0.25 M Na2S. When the ZnS/CdS/TiO2 photoanode equipped with the PEC cell were operated at the optimal conditions, a maximum photocurrent density (8.17 mA/cm2) and photoconversion efficiency (3.56%) could be achieved. Moreover, the hydrogen generation rate reached to 87.98 mol/cm2-h with a long-term stability. As compared with CdS/TiO2 photoanode, the studied ZnS/CdS/TiO2 photoanode exhibited not only a promotion in photoactivity but also an increase in the hydrogen production rate. The lifetime of photoanode was increased as well, owing to the reduction in photocorrosion of photoanode.

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