All-Scale Structural Optimization of Resiliently Crystalline Na–Ce–Sn–S Chalcogel for Efficient Oxygen Evolution Reaction Electrocatalyst

Abstract

The metal cation linker in metathesis-derived chalcogels critically governs structural evolution, porosity, and resultant physicochemical properties. However, most studies have emphasized atomic-scale functionality of metal linker within chalcogel network, with limited attention to local structural transformation and even long-range ordering. This work demonstrates the unprecedented role of cerium ions in directing the formation of a sustainable 2D crystalline Ce–Sn–S (CTS) chalcogel. The crystalline framework arises from coordination transformation of SnS4 tetrahedra within Sn2S6 dimers into distorted Sn3S4 broken-cube clusters, yielding a [Sn3S7]n2n− layered geometry. Cerium oxidation states, particularly Ce3+ enrichment, further stabilize the crystalline network via a templating effect and enhance electrocatalytic activity. The optimized CTS-5 chalcogel exhibits superior oxygen evolution reaction performance, including a low overpotential of 300 mV at 10 mA cm−2, the lowest Tafel slope of 80 mV dec−1, and stable operation for 50 h at 10 mA cm−2. The crystalline CTS chalcogel represents a new class of aerogel materials, where robust 2D crystallinity persists even under high cation loading, enabling functional tunability without compromising network integrity.