Robert Godin1
The University of British Columbia1
Robert Godin1
The University of British Columbia1
Polymeric photocatalysts made of Earth-abundant elements have been extensively developed over the past decade to take advantage of their synthetic tunability.<sup>1</sup> Within this family, carbon nitrides (CN<sub>x</sub>) are emerging as leading photocatalysts because of their high photocatalytic performance combined with good stability and facile synthesis.<sup>2,3</sup> However, significant gaps remain in our knowledge of the photophysical properties of these organic polymeric materials. Determining the pathways and mechanism of photoinduced processes will greatly aid our efforts to engineer better CN<sub>x</sub> photocatalysts for solar fuel production and other photocatalytic processes.<br/>We are taking the next step to develop a full picture of the charge carrier dynamics by expanding our spectroscopic capabilities to transient absorption <i>microscopy</i> (TAM). Notably, our first-of-its-kind TAM system monitors the microsecond – second timescales relevant to the complex multi electron redox reactions that occur to produce solar fuels. Spatial mapping of the charge carrier dynamics on the micron scale provides novel insights into the heterogeneity in individual CN<sub>x</sub> particles. This new tool allowed us to unearth a multiscale heterogeneity where the charge carrier dynamics differ from particle to particle and different behavior within individual particles on ~ 10 micrometer length scales can be observed. These new insights into the heterogeneity of charge carrier dynamics in CN<sub>x</sub> particles can push the field into uncovering the optimal structure and local environment in defect-rich organic semiconductors such as CN<sub>x</sub>. We are taking this knowledge and applying it to systems of biomass photoreforming for the simultaneous breakdown of organic matter and H<sub>2</sub> evolution.<br/> <br/>(1) Wang, Y.; Vogel, A.; Sachs, M.; Sprick, R. S.; Wilbraham, L.; Moniz, S. J. A.; Godin, R.; Zwijnenburg, M. A.; Durrant, J. R.; Cooper, A. I.; Tang, J. Current Understanding and Challenges of Solar-Driven Hydrogen Generation Using Polymeric Photocatalysts. <i>Nat. Energy</i> <b>2019</b>, <i>4</i> (9), 746–760. https://doi.org/10.1038/s41560-019-0456-5.<br/>(2) Liu, C.; Liu, J.; Godin, R. ALD-Deposited NiO Approaches the Performance of Platinum as a Hydrogen Evolution Cocatalyst on Carbon Nitride. <i>ACS Catal.</i> <b>2023</b>, <i>13</i> (1), 573–586. https://doi.org/10.1021/acscatal.2c04795.<br/>(3) Ohemeng, P. O.; Godin, R. Methylated Precursor Leads to Carbon Nitride (CNx) with Improved Interfacial Interactions for Enhanced Photocatalytic Performance. <i>Sustainable Energy Fuels</i> <b>2023</b>. https://doi.org/10.1039/D2SE01636B.