太陽能已被宣佈為台灣新能源政策中的積極推動的綠色能源之一，為了達到充分利用和儲存間歇性太陽能，開發一種高效穩定的太陽能儲能系統，將具有其重要意義和利益。光電化學（PEC）水分解被認為是具有前景且可有效轉換存儲太陽能的途徑之一。
在本研究中，我們探討CuBi2O4奈米異質接面光電極（nanoCuBi2O4）用於光電化學水分解的製備與應用。nanoCuBi2O4首先在摻氟的氧化錫導電玻璃基板(FTO)上電沉積BiOI奈米片陣列（nanoBiOI）為基板，然後通過滴鍍VO2+及/與Cu2+的乙醇前驅體液與熱處理後，轉化為nanoCuBi2O4|CuO光陰極或nanoBiVO4|CuBi2O4光陽極。通過調節乙醇前體液的用量和組成，調控nanoCuBi2O4|CuO和nanoBiVO4|CuBi2O4在nanoBiOI的轉化程度。透過採用掃描電子顯微鏡、紫外光-可見光譜、X光繞射儀、線性掃描伏安法、計時電流法和電化學阻抗等分析方法對nanoCuBi2O4進行物性、化性的表徵研究。
結果顯示，前驅體的用量和組成對nanoCuBi2O4的表面形貌和光電化學性能有很大影響。在最佳合成條件下，nanoCuBi2O4|CuO光陰極呈現出奈米孔洞狀結構，並表現出高起始電位（1.1 V vs RHE）和光電流響應（0.2 V vs RHE -0.35 mA cm-2）的良好光電化學性能，另一方面，nanoBiVO4|CuBi2O4光陽極在1.23 V vs RHE下顯示出1.29 mA-2cm-2的光電流響應，相較於原始的BiVO4，起始電位陰極位移了120 mV同時光電流約提升了兩倍。異質接面用於提升整體光電化學性能的關鍵決定因素已於本研究中探討發現。

Solar energy has been announced as one of first-tier renewable energies in Taiwan’s New Energy Policy, and to well-utilize and store the intermittent solar energy, developing an efficient and stable solar-to-chemical conversion device is therefore of great importance and interests. Photoelectrochemical (PEC) water splitting has been considered as one of the promising approaches to convert storage solar energy.
This work reports on the fabrication and applications of CuBi2O4 nano-heterojunction photoelectrodes (nanoCuBi2O4) for photoelectrochemical (PEC) water splitting. (nanoCuBi2O4) were fabricated by firstly electrodepositing of BiOI nanosheet array (nanoBiOI) as a template on the flourine-doped tin oxide coated glass substrate, followed by its conversion into nanoCuBi2O4|CuO photocathode or nanoBiVO4|CuBi2O4 photoanode via drop-casting an ethanolic VO2+ and Cu2+ precursor solution and a subsequent thermal treatment. The degree of conversion of nanoBiOI into nanoCuBi2O4|CuO and nanoBiVO4|CuBi2O4 were controlled by adjusting the dosage and composition of the ethanolic precursor solution. The physiochemical properties of nanoCuBi2O4 were characterized using scanning electron microscope, UV-vis spectroscopy, X-ray diffraction, linear sweep voltammetry, chronoamperometry, and electrochemical impedance spectroscopy.
It was found that the dosage of the precursor had a great influence on the surface morphology and PEC properties of nanoCuBi2O4. Under optimal synthetic conditions, nanoCuBi2O4|CuO photocathode exhibited nanosheet structure and exhibited promising PEC performance, including high onset potential (1.1 V vs. RHE) and photocurrent response (-0.35 mA cm-2 at 0.2 V vs RHE). nanoBiVO4|CuBi2O4 photoanode, on the other hand, showed a photocurrent response of 1.29 mA-2 cm-2 at 1.23 V vs RHE, which is about two times higher than that of pristine BiVO4 with 120mV cathodic shift onset potential. The key factors in determining the overall PEC performance using heterojunction strategy have been uncovered and discussed.

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