PHI/PTI-single-atoms controlled synthesis and energy applications

Abstract

This direct doctorate proposal will start with the synthesis of the Single-Atom Catalysts (SACs) based on PTI and transition metals. As soon as the synthesis of the photocatalytic system is completed, as well as part of its characterization, they will be tested in photocatalytic reactions, we plan to start with the water-splitting reaction using our infrastructure, simultaneously we intend to start the photocatalytic CO2 reduction in collaboration with Prof. Lucia Mascaro (LIEC-UFSCar). As mentioned in the body of the proposal, in the water-splitting reaction the focus will be on the proton reduction reaction (Eq.1), which is the most common approach for this photocatalytic reaction. At first, we will use the conditions commonly used in the literature, which involves the addition of sacrificial reagents. 2H+(aq) + 2e-  H2(g)(Eq. 1). Depending on the results the next challenge will be to couple the reaction of proton reduction (Eq.1) with water oxidation (Eq. 2) to operate simultaneously photocatalysed by a unique PHI/PTI-Single Atom system. H2O(l)  1/2O2(g) + 2H+(aq) + 2e-(Eq. 2)In the CO2 reduction, the main goal will be to obtain methanol the most desired product from the CO2 reduction (Eq. 4). Therefore, we will use the conditions reported in the literature that favours this product. CO2 + 6H+ + 6e-  CH3OH + H2O (Eq. 4). There are in the literature many reports of the CO2 reduction into CH4 (Eq. 5) photocatalysed by polymeric carbon nitride doped with metal nanoparticles. Hence, we also plan to test these conditions later. CO2 + 8H+ + 8e-  CH4 + 2H2O (Eq. 5). Once the first PHI/PTI-Single-Atoms active systems were discovered, the Ph.D. student will investigate their mechanism and study deeper their photocatalytic activity (e.g. close the carbon balance, experiments with isotopes combined with MS-Spectrometry, in-situ characterization, etc) in collaboration with Prof. Edman Tsang (University of Oxford-UK) during his/her BEPE internship, as already agreed with Prof. Edman Tsang (see support letter in the SI). When the Ph.D. student comes back from his/her BEPE internship is expected that the mechanism of action for the active PHI/PTI-Single-Atoms systems will already be completely understood. These results certainly will be more than enough for one or more high-impact publications and possibly a patent, as well. At this stage, the project focus will be to use the mechanism data obtained to retro-design the most actives PHI/PTI-Single-Atoms systems in a controlled way, in order to improve their efficiency and selectivity. (AU)