カタリストのリドックス状態と反応ダイナミクスを追跡する Ni-Fe オキシヒドロキシド 酸素進化反応 電気触媒:触媒のサポートと電解質の pH の役割
Mikaela Görlin1,2, Jorge Ferreira de Araújo1, Henrike Schmies1
1Department of Chemistry, Chemical Engineering Division, Technical University of Berlin , Straße des 17. Juni 124, 10623, Berlin, Germany.
Journal of the American Chemical Society
|January 13, 2017
まとめ
導電性サポーターと高いpHは,酸素進化反応 (OER) のニッケル鉄酸化水酸化物電解剤の性能を大幅に高め,酸化還元作用と活性性を高めます.
科学分野:
- 電気化学
- 材料科学
- カタリシス
背景:
- ニッケル鉄酸化水酸化物は,アルカリ媒体の酸素進化反応 (OER) の重要な電気触媒であり,電気化学的エネルギー変換に不可欠である.
- 導電基材や電解質のpHなどの外部要因が触媒性能に及ぼす影響を理解することは,OERの最適化に不可欠です.
研究 の 目的:
- 導電媒介と電解質のpHが,Ni-Feオキシヒドロキシド電触媒の酸化還元作用とOER活性に与える影響を調査する.
- これらの効果を制御する根本的なメカニズムを,先端の局所光学および電気化学技術を用いて解明する.
主な方法:
- 酸化ニッケル種を監視するために,in situ UV-vis スペクトロ-電気化学.
- ガス進化分析とファラダイク効率のための電気化学質量スペクトロメトリー (DEMS) を操作する.
- 詳細な電子構造分析のためのインサイト冷凍X線吸収光譜 (XAS)
- リドックスピークの行動とpH依存性を研究するサイクル電圧測定法.
主要な成果:
- 導電性サポーターとpH> 13は,Ni-Feオキシヒドロキシドの酸化還元活性とOER触媒性能 (2〜3倍増加) を有意に高めました.
- より高いpH値は,OERとNi酸化ポテンシャルをカソディックにシフトさせ,特定の陽子-電子転送メカニズムを示唆する,非単調なpH依存性を明らかにした.
- 場所での紫外線検査では,以前より高いpHでNi酸化が確認され,Fe含有量が増加している混合Ni-FeセンターでNiの分数が減少していることが示されました.
結論:
- 電解質のpHと導電性サポーターは,Ni-Feオキシヒドロキシドの酸化還元化学を調節し,OER活性を増強する上で重要な役割を果たします.
- この発見は,陽子電子伝送プロセスと,Ni-Fe酸化水酸化物の電気触媒におけるFeの役割に関する新しい機械的洞察を提供します.
- この研究は,電気化学エネルギーアプリケーションのためのアルカリ性OER触媒の最適化に関するより深い理解を提供します.
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