Developing isolated single metal ion coordinated by carbon nitrides for photocatalytic H2O2 production based on Time-Dependent Density Function Theory

我们展示了一种极化工程策略，通过将(硫代)尿素官能团接枝到共价三嗪骨架(CTF)上，显著地促进了电荷分离/传输和明显增强了质子转移。我们的计算研究表明，这是由于改进的电荷分离和硫脲上高度集中的空穴而显著增强了2电子氧还原反应。我们还利用喷雾热解沉积的方法在镀钼玻璃上制备了平坦而均匀的多晶Cu3BiS3(CBS)薄膜(Mo-SLG)，以生成过氧化氢(H_2O_2)。光电化学(PEC)合成是通过间接生成与H_2O_2不成比例的2E-ORR初始超氧化物进行的。我们计算了对称配位钴单原子上的水氧化能力及其对甲烷光催化氧化的影响。结果表明，具有2N和2C配位Co中心的单钴原子PCN光催化剂在光催化过程中对单电子转移水氧化反应具有理想的电子构型，水的活化促进H的传质生成H_2O_2是三嗪中心上2E-ORR过程的速率控制步骤。以SAC_Au-KPCN为例，K4s和Au5d轨道的重叠产生了浅陷阱能级，使高浓度空穴聚集在Au位，从而显著加速了H2O的活化，并显著提高了过氧化氢的生成活性。

We demonstrate a polarization engineering strategy by grafting (thio)urea functional groups onto covalent triazine frameworks (CTFs), giving rise to significantly promoted charge separation/transport and obviously enhanced proton transfer. Our calculation studies reveal the performance is attributed to the prominently enhanced 2-electron oxygen reduction reaction by improved charge separation and highly concentrated holes at the thiourea site.We also a prepared a flat and uniform polycrystalline Cu3BiS3 (CBS) thin film on a molybdenum-coated glass (Mo-SLG) by spray pyrolysis deposition for generation of hydrogen peroxide (H2O2). The photoelectrochemically (PEC) synthesis proceeds by an indirect 2e－ ORR initial formation of superoxide, which is disproportionate to H2O2.We calculated the water oxidation ability and its influence on photocatalytic oxidation of CH4 over symmetrically coordinated cobalt single-atom. It is revealed that the single-cobalt-atom PCN photocatalyst with 2N and 2C coordinated Co center possesses a desired electronic configuration for one electron transfer water oxidation reaction during photocatalysis.The activation of water for boosting the mass transfer of H to form H2O2 is found to be the rate-determined step during the 2e- ORR process on triazine sites. Taking SAC_Au-KPCN as an example, the overlap of K 4s and Au 5d orbitals generated a shallow-trapped energy level for accumulation of highly-concentrated holes at Au sites, thus leading to an significantly accelerated H2O activation and a remarkably boosted activity for H2O2 production.