ナノ構造のトングステン三酸化物フォトアノードにおける水酸化と電子抽出運動

Sacha Corby¹, Laia Francàs¹, Shababa Selim¹

¹The Department of Chemistry , Imperial College London , South Kensington, London SW7 2AZ , U.K.

Journal of the American Chemical Society

|November 2, 2018

まとめ

トングステン三酸化物 (WO3) の光電極運動を理解することは,効率的な水の酸化に不可欠です. WO3は,他の金属酸化物とは異なり,電子抽出よりも速い水酸化を示し,再結合損失を最小限に抑えます.

科学分野:

材料科学
光触媒
電気化学

背景:

効率的な水酸化は再生可能エネルギー技術の鍵です
移行金属酸化物は有望な光電極材料ですが,その効率は再結合によって制限されています.
光アノードの性能を最適化するには,反応運動を理解することが不可欠です.

研究の目的:

トングステン三酸化物 (WO3) フォトアノードにおける水酸化と電子抽出の運動競争を調査する.
表面再結合と全体的な水酸化効率とこれらの運動を相関させる.
電子抽出運動における酸素空間の役割を解明する.

主な方法:

反応運動を監視するために,一時的な拡散反射スペクトロスコーピーを用いる.
電子の抽出を評価するための一時的な光流測定.
酸素空隙の密度を調節するために,異なる偏差とフィルム処理を適用した研究.

主要な成果:

トングステン三酸化物 (WO3) は,電子抽出 (∼10 ms) よりも速い水酸化運動 (ミリ秒) を表している.
WO3の電子抽出は,他の金属酸化物 (例えば,TiO2,α-Fe2O3,BiVO4) よりも遅いため,酸素の空間に電子が閉じ込められる.
電子抽出が遅いにもかかわらず,WO3は控えめな電荷再結合損失とフラットバンドに近い光電流発生の可能性を示している.

結論:

酸化バレンスの帯に起因するWO3の急速な水酸化運動は,表面再結合を上回ります.
WO3の酸素空白は浅いトラップ状態を作り,電子抽出を遅らせますが,再結合を大幅に増加させません.
WO3の独特の運動プロファイルは,効率的な水酸化のための光触媒における熱力学的推進力の重要性を強調しています.

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