Sustainable energy is the need of the hour to cater the global energy demands with zero carbon emissions. Solar energy is the ultimate, clean and renewable form of energy that can be harvested to split water molecules into molecular hydrogen, a clean fuel with energy density 120 MJ Kg⁻¹. Homometallic metal organic frameworks (MOFs), an emerging class of porous crystalline materials with tunable porosity and structural controllability, chemical and thermal stabilities, and recyclability, are proclaimed as potent semiconducting photocatalysts for water splitting reactions. Despite these peculiar advantages, there are still many open challenges to tailor MOFs as well-versed photocatalysts because of their certain inadequacies such as UV activity and limited catalytic efficiency. Introduction of structural heterogeneity into the MOF systems via the incorporation of other metal ions or the different organic linkers is envisioned as an unambiguous strategy to ameliorate the performance of the MOFs. Subsequently, the heterogeneity in the mixed metal-MOFs (MM-MOFs) infers the synergistic interactions between the metal orbitals within the framework to bring accentuated enhancement in the catalytic properties, and encapsulation of photoactive antennae leading to the improved photosensitizing properties in the visible region. This review article summarizes the various synthetic approaches to MM-MOFs with their applications in photocatalytic hydrogen production by water splitting reactions.

可持续能源是满足零碳排放的全球能源需求的迫切需要。太阳能是一种终极、清洁和可再生的能源形式，可以通过收集将水分子分解成分子氢，这是一种能量密度为 120 MJ Kg ^{-1的清洁燃料}. 同质金属有机框架 (MOF) 是一类新兴的多孔晶体材料，具有可调的孔隙率和结构可控性、化学和热稳定性以及可回收性，被宣布为用于水分解反应的有效半导体光催化剂。尽管有这些特殊的优势，但由于 MOF 存在紫外线活性和催化效率有限等某些不足，因此将 MOF 定制为精通的光催化剂仍然存在许多开放性挑战。通过将结构异质性引入 MOF 系统其他金属离子或不同有机连接体的结合被设想为改善 MOF 性能的明确策略。随后，混合金属-MOFs（MM-MOFs）的异质性推断框架内金属轨道之间的协同相互作用，从而增强了催化性能，并且封装了光活性天线，从而提高了可见光区域的光敏性能. 这篇综述文章总结了 MM-MOF 的各种合成方法及其在水分解反应光催化制氢中的应用。