Lin Jiahe, Chen Xiaowei, Zhang Bofeng, Tan Chunrong, Lin Qiubao, Wang Xiulin
School of Science, University Xiamen 361021 China
Semiconductor Industry and Technology Research Institute, Jimei University Xiamen 361021 China.
RSC Adv. 2022 Oct 24;12(47):30349-30358. doi: 10.1039/d2ra06121j.
Two-dimensional (2D) carbon allotropes with all-sp-hybridization have demonstrated great potential in nano-photoelectric devices, but the application of semiconductor photocatalysts for water splitting and anodes in magnesium batteries remains unoptimistic. Motivated by this, we theoretically study a highly stable all-sp-hybridized 2D carbon allotrope twin T-graphene (TTG) first-principles simulations. And through the calculations of the HSE06 functional, we find that TTG has a wide bandgap (2.70 eV) and suitable band edge positions satisfying the criteria of photocatalysts for overall water splitting. Additionally, TTG exhibits excellent photocatalytic properties for overall water splitting reflecting a high STH efficiency (12.34%), strong absorption coefficient in the visible-light region and the carrier mobility being high for electrons but low for holes. By investigating the strain effects, we get that, with biaxial compressive strain, the ability of overall photocatalytic water splitting can be effectively improved including STH up to ∼30%. Moreover, the bulk TTG also exhibits great potential as an anode material of magnesium batteries with a theoretical capacity of 556 mA h g, average voltage of 0.74 V and diffusion energy barrier of ∼0.96 eV. Our results would broaden the application of all-sp-hybridized 2D carbon allotropes in the semiconductor photocatalytic and magnesium batteries field.
具有全 sp 杂化的二维（2D）碳同素异形体在纳米光电器件中已展现出巨大潜力，但半导体光催化剂在水分解及镁电池阳极方面的应用仍不容乐观。受此启发，我们通过第一性原理模拟对一种高度稳定的全 sp 杂化二维碳同素异形体孪晶 T 型石墨烯（TTG）进行了理论研究。通过 HSE06 泛函计算，我们发现 TTG 具有较宽的带隙（2.70 eV）以及合适的带边位置，满足全水分解光催化剂的标准。此外，TTG 在全水分解方面表现出优异的光催化性能，其太阳能到氢能转化效率（STH）高达 12.34%，在可见光区域具有较强的吸收系数，电子载流子迁移率高而空穴载流子迁移率低。通过研究应变效应，我们发现，在双轴压缩应变下，全光催化水分解能力可得到有效提高，STH 可达约 30%。此外，块状 TTG 作为镁电池的阳极材料也展现出巨大潜力，其理论容量为 556 mA h g，平均电压为 0.74 V，扩散能垒约为 0.96 eV。我们的结果将拓宽全 sp 杂化二维碳同素异形体在半导体光催化和镁电池领域的应用。
