Mishra Biswajit, Mishra Sabyasachi, Satpati Biswarup, Chaudhary Yatendra S
Materials Chemistry Department, CSIR-Institute of Minerals and Materials Technology, Bhubaneswar, 751 013, Odisha, India.
Surface Physics and Material Science Division, Saha Institute of Nuclear Physics, Kolkata, 700 064, India.
ChemSusChem. 2019 Jul 19;12(14):3383-3389. doi: 10.1002/cssc.201900388. Epub 2019 Jun 26.
The design of an efficient and highly selective organic polymeric semiconductor photocatalyst consisting of Earth-abundant elements for solar fuel generation using seawater, and also deionized water, as a proton source is reported. The mesoporous g-C N synthesized using a conventional precursor (urea) shows significant H generation (ca. 33 000 μmol h g ) and drives the photoreduction of CO to CH , along with trace amount of methanol. However, when the chosen precursor cyanamide is used, drastic improvement in H generation (ca. 41 600 μmol h g ) and CO photoreduction is observed. The introduction of a surface nitrogen deficiency and modification of the surface with Cu further enhances solar H generation (ca. 50 000 μmol h g ) and CO photoreduction (3.12 μmol h g ) activity, respectively, owing to improvement in light harvesting and charge separation, as revealed by a shorter average lifetime of 3.52 ns and higher Stern-Volmer quenching constant value of approximately 11.2 m . In addition, improved selectivity in CO photoreduction to only CH is also observed. The designed photocatalytic system is stable, with the solar H generation rate increasing even after 20 h under continuous illumination with a turnover number of 6500. When seawater used instead of deionized water, the overall solar fuel generation efficiencies of all photocatalysts marginally decreased owing to a decrease in the photogenerated charge-carrier separation efficacy.
报道了一种高效且高选择性的有机聚合物半导体光催化剂的设计，该催化剂由地球上储量丰富的元素组成，用于利用海水以及去离子水作为质子源来产生太阳能燃料。使用传统前驱体（尿素）合成的介孔g-CN显示出显著的氢气生成量（约33000μmol h g），并能驱动CO的光还原生成CH，同时伴有痕量甲醇。然而，当使用选定的前驱体氰胺时，氢气生成量（约41600μmol h g）和CO光还原有了显著提高。表面氮缺陷的引入以及用Cu对表面进行修饰，分别进一步提高了太阳能制氢（约50000μmol h g）和CO光还原（3.12μmol h g）活性，这是由于光捕获和电荷分离得到改善，平均寿命缩短至3.52ns以及斯特恩-沃尔默猝灭常数约为11.2m更高所揭示的。此外，还观察到CO光还原生成CH的选择性提高。所设计的光催化系统稳定，在连续光照20小时后太阳能制氢速率仍在增加，周转数为6500。当使用海水代替去离子水时，由于光生电荷载流子分离效率降低，所有光催化剂的整体太阳能燃料生成效率略有下降。
