二硒化鈷修飾於矽微米柱之異質結構作光陰極水分解

A Heterostrucure of CoSe2 on Silicon Microwires as a Photocathode for Water Splitting

張致維(Zhang Zhi-Wei)

指導教授 ： 胡淑芬

國立臺灣師範大學/理學院/物理學系/碩士(2016年)

https://doi.org/10.6345/NTNU202205146

摘要

發展可應用於光電化學產氫反應之高效率且極穩定之共催化劑於現今為一非常迫切之議題，使用共催化劑過渡金屬二硫屬化物(transition metal dichalcogenides)為目前常見提升光催化水分解效率方法之一。本實驗第一部分將修飾二硒化鈷(CoSe2)於矽微米柱上作為一個光催化產氫之光陰極1，由於二硒化鈷具有半金屬特性，使得電荷能有效地從矽微米柱傳輸至共催化劑及電解液進行氫還原反應。修飾適量二硒化鈷於矽微米柱後將使光電流起始電壓被提升至0.18 V vs RHE，且於0 V vs RHE之光電流密度更達9 mA/cm2。
然而，二硒化鈷修飾於矽微米柱之光陰極無法長時間於酸性溶液環境下進行光催化產氫反應，因此於實驗第二部分將解決此問題。將二硒化鈷鑲嵌於片狀氮化碳成為一穩定光催化水分解之共催化劑，此乃因片狀氮化碳能使載子更快傳導至水溶液，降低電荷累積於電極表面之發生機率，進而提升光陰極於酸性溶液進行光催化產氫之穩定度達3.5小時。

關鍵字

二硒化鈷 ； 矽微米柱 ； 光電化學 ； 產氫

並列摘要

It’s very urgent to develop high efficient and extremely stable cocatalyst as an alternative to nanobelt transition metal cocatalyst for photoelectrochemical hydrogen evolution reaction in the present. Using transition metal dichalcogenide is a very common way to enhance the efficiency of photoelectrochemical water splitting. In the first part of this experiment, we will decorate CoSe2 on silicon microwires as a photocathode for photoelectrochemical hydrogen evolution. Orthorhombic CoSe2 makes the charge transfer faster from silicon microwires to cocatalyst and electrolyte due to its semi-metallic nature. With proper amount of CoSe2 decorated on silicon microwires will enhance the onset potential to 0.18 V vs RHE and enhance the photocurrent density to 9 mA/cm2.
However, CoSe2/Si MWs can’t maintain the photoelectrochemical hydrogen evolution in acid solution for a long time, therefore we will solve this problem in the second part of this experiment. We embedded the CoSe2 into g-C3N4 to be a stable cocatalyst for photoelectrochemical water splitting due to fast charge transportation from photocathode to electrolyte, then decrease the charge accumulation on the surface of photocathode further make the stability of photoelectrochemical hydrogen evolution in acid solution can be up to 3.5 hr.

並列關鍵字

CoSe2 ； silicon microwire ； photoelectrochemical ； hydrogen evolution

參考文獻

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