Rational design of carbon nitride photocatalysts by identification of cyanamide defects as catalytically relevant sites

Author(s)

Lau, Vincent Wing-hei ; Moudrakovski, Igor ; Botari, Tiago ; Weinberger, Simon ; Mesch, Maria B. ; Duppel, Viola ; Senker, Juergen ; Blum, Volker ; Lotsch, Bettina V.

• Document type: Journal article
• Source: NATURE COMMUNICATIONS; v. 7, JUL 2016.
• Web of Science Citations: 139

Abstract

The heptazine-based polymer melon (also known as graphitic carbon nitride, g-C3N4) is a promising photocatalyst for hydrogen evolution. Nonetheless, attempts to improve its inherently low activity are rarely based on rational approaches because of a lack of fundamental understanding of its mechanistic operation. Here we employ molecular heptazine-based model catalysts to identify the cyanamide moiety as a photocatalytically relevant `defect'. We exploit this knowledge for the rational design of a carbon nitride polymer populated with cyanamide groups, yielding a material with 12 and 16 times the hydrogen evolution rate and apparent quantum efficiency (400 nm), respectively, compared with the unmodified melon. Computational modelling and material characterization suggest that this moiety improves coordination (and, in turn, charge transfer kinetics) to the platinum co-catalyst and enhances the separation of the photogenerated charge carriers. The demonstrated knowledge transfer for rational catalyst design presented here provides the conceptual framework for engineering high-performance heptazine-based photocatalysts. (AU)

• FAPESP's process: 14/11986-7 - Ab initio investigation of mechanical, vibrational and electronic properties of carbon nitride materials
• Grantee: Tiago Botari
• Support Opportunities: Scholarships abroad - Research Internship - Doctorate