近年來環保意識抬頭，能源轉型迫在眉睫。再生能源的使用比例逐年提高，能源效率必須提升。歐洲國際能源總署公佈的技術藍圖：氫和燃料電池報告中明白揭露2050年氫和燃料電池將是關鍵低碳技術。以綠色製程的角度來看，氫氣的產生也必須從非化石資源。然而直接使用光電極分解水產生氫氣與氧氣，氧氣的生成端是速率決定步驟。本計劃提出的構想便是在光陽極進行選擇性氧化反應，將生質物(Biomass)轉化成具有經濟價值的化學品，作為工業前驅物；光陰極則是進行水的還原反應產生氫氣。此設計可提高產氫效率同時增加反應系統的附加價值。不過目前的光電化學反應系統仍受限於光觸媒材料的光吸收度較低，光生載子的再結合率高，觸媒-電解質界面的反應速率慢等問題，造成太陽能轉換化學能的效率偏低，無法與既有技術競爭。此計畫之構想便是分別優化光陽極與光陰極，能帶設計匹配生物質轉化的氧化還原電位，有系統探討選擇性氧化反應關鍵參數，預計三年內完成的項目如下：1. 優化光陽極與光陰極，噴塗法製備n型(光陽極)與p型(光陰極)半導體光吸收層，吸收層的保護膜，以及輔觸媒裝載。2. 載子傳輸機制探討，電化學分析(EIS/IMPS/IMVS)傳輸阻抗，時間解析光譜分析載子傳輸動力。3. 建構原位、即時的分析系統4. 選擇性氧化反應機制探討，建立反應動力學模型。 ;With increasing awareness of environmental protection for our planet and the needs for energy transition, the utilization of renewable energies and enhancement of energy efficiency are critical. It is clear that from the Technology Roadmap published by International Energy Agency, in 2050 hydrogen and fuel cells will be the key low-carbon technologies. From this perspective, hydrogen must be produced from non-fossil resources. Photocatalytic hydrogen production from water is one of the options. However, oxygen production directly from water splitting is not kinetically favorable. Here, we propose a photoelectrochemical (PEC) system to perform a selective oxidation of biomass-derived chemicals. Hydrogen is produced at the cathode and valuable chemicals are synthesized at the anode, increasing both the efficiency and selectivity of solar-to-chemical conversion. Unfortunately, most photocatalyst materials suffer from low efficiency due to the limited range of light absorption, high electron-hole recombination rates, and low reaction kinetics at the active sites, making PEC system difficult to compete with traditional production process. The keys to enhanced solar-to-chemical conversion are the optimization of the photoanode and the photocathode, band engineering to match the redox potentials of biomass conversion reactions, and understanding of the reaction mechanism. In this three-year project, our approach to solving these problems involves the following strategies:1. Optimization of the photoanode and the photocathode, including n-type and p-type absorber, protection layer, and co-catalyst.2. Investigation of charge-transfer mechanism of photo-generated carriers: charge transport impedance studies using electrochemical methods (EIS/IMPS/IMVS) and charge transport dynamics using time-resolved techniques (transient absorption)3. Construction of in-situ and operando analysis system.4. Understanding of the selective chemical reaction kinetics and mechanism.
