Nano magnesium oxide has wide applications, and MgO with (111) facets has wider potential applications than MgO with (100) facets (e.g., in catalysis and adsorption). However, nano MgO with (111) polar faces has not been studied throughly, so the preparation of nano-octahedral MgO (N-O-MgO) with eight exposed (111) facets remains a great challenge. Herein, we successfully synthesised N-O-MgO via an effective solvothermal-solid-decomposition method and studied its adsorption performance. The obtained N-O-MgO showed excellent performance (229.36 mg g−1) for methyl orange (MO). The adsorption follows the pseudo-second-order kinetic equation and the Langmuir isotherm model. The dimensionless parameter RL (0.042) and Gibbs free energy ΔG (−6.538 kJ mol−1) revealed that the adsorption of MO on N-O-MgO was a spontaneous and feasible process. The adsorption of MO and methyl blue (MB) on N-O-MgO were studied to determine the adsorption sites. Based on these experiments and analysis, it was determined that the adsorption sites were magnesium ions and the adsorption mechanism was proposed to describe the adsorption process.
Xingyu Zhang,Lingling Wang,Yawei Wang,Xiangyang Zhao,Rong Fang,Rui Guo,Yue Zhou,Xintong Zhang,Yichun Liu
Modifying the back contact interface plays a key role in improving the efficiency of Cu2ZnSn(S,Se)4 (CZTSSe) solar cells. Aiming at the phase decomposition and carrier recombination issues in the CZTSSe/Mo back contact interface, an ultra-thin Mg(OH)2 intermediate layer was introduced between the Mo substrate and the CZTSSe absorber layer. The Mg(OH)2 intermediate layer effectively suppressed the interface phase decomposition reactions and inhibited the generation of interface secondary phases. Meanwhile, during the high-temperature selenization process, the Mg2+ doped into CZTSSe at the back contact interface, reducing the defects and band offset at the CZTSSe/Mo interface. The performance of the device was improved, with a significant increase in efficiency compared to the control device. This work highlights the modification effect of Mg(OH)2 for improving back contact and also provides an easy-handling method to achieve high-performance CZTSSe solar cells.