A General Polymer-Oriented Acid-Mediated Self-Assembly Approach toward Crystalline Mesoporous Metal Sulfides

Mesoporous metal sulfides (MMSs) with high surface areas and large pore volumes show great potential in many applications such as gas sensing, photodetection, and catalysis. However, the synthesis of MMSs is still challenging due to the uncontrollable fast precipitation between metal ions and S^2- ions and the large volume contraction during the conversion of metal precursors to sulfides. Here, a general polymer-oriented acid-mediated self-assembly method to synthesize highly crystalline MMSs (e.g., ZnS, CdS, Ni₃ S₄ , CuS, and Zn_x Cd_{1- x} S) by using polyethylenimine (PEI) as pore-forming agent is reported. In this method, acetic acid is designed as pH regulator and coordination agent to control the interactions between inorganic precursors and PEI, and adjust the reaction kinetics of metal ions and thioacetamide. This method endows a high degree of control over crystal structure and porous structure of MMSs. The surface areas and pore volumes of obtained MMSs are as high as 157 m² g^-1 and 1.149 cm³ g^-1 , respectively. Benefiting from the abundant mesopores and homojunctions, mesoporous Zn_0.56 Cd_0.44 S shows a superior photocatalytic H₂ generation rate of 14.3 mmol h^-1 g^-1 .