Facile formation of CoN4 active sites onto a SiO2 support to achieve robust CO2 and proton reduction in a noble-metal-free photocatalytic system
Facile formation of CoN4 active sites onto a SiO2 support to achieve robust CO2 and proton reduction in a noble-metal-free photocatalytic system
复制标题
在 SiO2 载体上轻松形成 CoN4 活性位点，以在不含贵金属的光催化系统中实现稳健的 CO2 和质子还原
DOI：
10.1039/c9ta00949c
复制
发表时间：
2019-05-07
影响因子：
11.9
通讯作者：
Wang, Feng
中科院分区：
文献类型：
--
作者：
Hu, Jun-Chao;Gui, Meng-Xi;Wang, Feng
将CO2和质子转化为太阳能燃料（CO和H2）是人工光合作用的基础。迄今为止，大多数报道的钴基分子催化剂或单原子催化剂（SAC）具有CoN 4核结构。然而，这些金属络合物催化剂或SAC的制备需要复杂的有机配体合成方法或苛刻的材料制造条件。在这项研究中，通过Co2+离子与胺化SiO2纳米颗粒的自配位，实现了在SiO2载体上容易形成活性CoN 4结构。CoN 4结构的形成通过基于同步加速器的X射线吸收光谱来鉴定。CoN 4-SiO2催化剂在含有g-C3 N4作为光敏剂的光化学体系中表现出优异的介导CO2-到-CO和2 H +-到-H2转化的双功能活性。该系统稳定地生产具有高活性（5053 mmol g-1和36 mmol g-1 h-1）和显著稳定性（耐久性> 120 h）的合成气（CO + H2，CO/H2 = 1：1-1：2）。机理研究表明，Co（I）-物种是通过光诱导电子转移从g-C3 N4到CoN 4-SiO2产生的活性物种。Co ~（2+）从胺化SiO_2载体上的解离和g-C_3 N_4在辐照下的分解是该体系在长时间静置后失活的主要原因。
The conversion of CO2 and protons to solar fuels (CO and H2) is the basis of artificial photosynthesis. To date, most of the reported cobalt-based molecular catalysts or single-atom catalysts (SAC) feature a CoN4 core structure. However, the preparation of these metal complex catalysts or SACs requires either a complicated organic ligand synthesis method or harsh material fabrication conditions. In this study, the facile formation of an active CoN4 structure onto a SiO2 support was achieved via selfcoordination of Co2+ ions with aminated SiO2 nanoparticles. The formation of the CoN4 structure was identified by synchrotron-based X-ray absorption spectroscopy. The CoN4-SiO2 catalyst exhibited exceptional bifunctional activity of mediating the CO2-to-CO and 2H+-to-H2 conversions in a photochemical system containing g-C3N4 as a photosensitizer. The system robustly produced syngas (CO + H2, CO/H 2 = 1 : 1-1 : 2) with a high activity (5053 mmol g-1 and 36 mmol g-1 h-1 based on the catalyst) and remarkable stability (durability > 120 h). Mechanistic studies reveal that the Co(I)-species is the active species generated via a photoinduced electron transfer from g-C3N4 to CoN4-SiO2. The dissociation of Co2+ from the aminated SiO2 support and the decomposition of g-C3N4 under irradiation are the main reasons for the inactivation of the system after long-time photocatalysis.