Wu Shunnian, Senevirathna Hasanthi L, Weerasinghe P Vishakha T, Wu Ping
Entropic Interface Group, Engineering Product Development, Singapore University of Technology and Design, 8 Somapah Road, Singapore 487372, Singapore.
Materials (Basel). 2021 May 18;14(10):2640. doi: 10.3390/ma14102640.
The wide bandgap of 2D Mg(OH) inhibits its applications in visible-light photocatalytic applications. Besides, its mismatched band alignment to the redox potential of O/HO, brings about low efficacy of water-splitting performance. Therefore, to release the powder of 2D Mg(OH) in photocatalytic research, we explore anion doping strategies to engineer its electronic structure. Here, anion doping effects on electronic properties of 2D Mg(OH) are investigated by using DFT calculations for seven dopants (F, Cl, S, N, P, SO, and PO). We found (1) S, N and P doping remarkably reduces its band gap from 4.82 eV to 3.86 eV, 3.79 eV and 2.69 eV, respectively; (2) the band gap reduction is induced by the electron transfer to the dopant atoms; (3) F, Cl, SO, and PO doping shifts its valence band to be lower than the oxidation potential of O/HO to render its band structure appropriate for photocatalytic water splitting. These results suggest that not only electrical conductivity of 2D Mg(OH) can be increased but also their band structure be aligned by using the proposed anion doping strategy. These results enable a new photocatalytic materials design approach while offering exciting possibilities in applications of high-current electrolysis, chemical gas sensing, and photocatalysis.
二维Mg(OH)的宽带隙限制了其在可见光光催化应用中的应用。此外，其与O/HO氧化还原电位不匹配的能带排列导致水分解性能的效率较低。因此，为了在光催化研究中释放二维Mg(OH)粉末，我们探索了阴离子掺杂策略来设计其电子结构。在此，通过对七种掺杂剂（F、Cl、S、N、P、SO和PO）进行密度泛函理论（DFT）计算，研究了阴离子掺杂对二维Mg(OH)电子性质的影响。我们发现：（1）S、N和P掺杂分别显著地将其带隙从4.82 eV降低到3.86 eV、3.79 eV和2.69 eV；（2）带隙的降低是由电子转移到掺杂原子引起的；（3）F、Cl、SO和PO掺杂将其价带移至低于O/HO的氧化电位，使其能带结构适合光催化水分解。这些结果表明，通过所提出的阴离子掺杂策略，不仅可以提高二维Mg(OH)的电导率，而且可以调整其能带结构。这些结果为新型光催化材料设计方法提供了可能，同时在高电流电解、化学气体传感和光催化应用中展现出令人兴奋的前景。
