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Carbon nitride materials paired with Co atoms have been shown to be effective for CO₂photoreduction. 

Photoactive single-atom catalysts (SACs) are among the most exciting catalytic materials for solar fuel production. Different SACs, including our own Co SACs, have been prepared on graphitic carbon nitride (C3N4) for use in photocatalysis. Building on our prior success, we report here doped C3N4 using various supplemental carbon dopants as the support for Co SACs. The Co SAC on a dianhydride doped C3N4 showed the highest activity in photocatalytic CO2 reduction. Catalyst characterization was carried out to explore the origin of the enhanced activity of this particular Co SAC. The dianhydride doped C3N4 possesses unique microstructural features, including large inter-layer space and fibrous morphology, that could contribute to the enhanced photocatalytic activity. Our results further indicate that the dianhydride is the most effective dopant to incorporate aromatic moieties in C3N4, which resulted in improved charge separation and enhanced activity in photocatalysis. 

With the rapid development of high-power petawatt class lasers worldwide, exploring physics in the strong field QED regime will become one of the frontiers for laser–plasma interactions research. Particle-in-cell codes, including quantum emission processes, are powerful tools for predicting and analyzing future experiments where the physics of relativistic plasma is strongly affected by strong field QED processes. The spin/polarization dependence of these quantum processes has been of recent interest. In this article, we perform a parametric study of the interaction of two laser pulses with an ultrarelativistic electron beam. The first pulse is optimized to generate high-energy photons by nonlinear Compton scattering and efficiently decelerate electron beam through the quantum radiation reaction. The second pulse is optimized to generate electron–positron pairs by the nonlinear Breit–Wheeler decay of photons with the maximum polarization dependence. This may be experimentally realized as a verification of the strong field QED framework, including the spin/polarization rates. 

We investigate the suitability of using GeV laser wakefield accelerated electron beams to measure strong, B > 0.1 MT, magnetic fields. This method is explored as an alternative to proton deflectometry, which cannot be used for quantitative measurement using conventional analysis techniques at these extreme field strengths. Using such energetic electrons as a probe brings about several additional aspects for consideration, including beam divergence, detectors, and radiation reaction, which are considered here. Quantum radiation reaction on the probe is found to provide an additional measurement of the strength and length of fields, extending the standard deflectometry measurement that can only measure the path integrated fields. An experimental setup is proposed and measurement error is considered under near-term experimental conditions.