Porous coordination polymer-derived CeO$_2$-SnO$_2$@S-C heterojunction nanocomposite for supercapacitor and oxygen evolution reaction

Porous coordination polymers (PCPs) and derived nanocomposites have attained substantial attention for electrochemical energy conversion and storage technologies owing to their tunable frameworks and favorable electrochemical characteristics. Here, we present a route for preparing a CeO$_2$-SnO$_2$@S-C heterojunction nanocomposite derived from PCPs and investigate its supercapacitor and oxygen evolution reaction performance. In three-electrode setup, the heterojunction exhibits specific capacitance of 1756.5 F g$^{−1}$ at 1 A g$^{−1}$. Electrochemical impedance analysis reveals a charge-transfer resistance as low as 1.76 Ω, indicating high conductivity together with fast charge transport kinetics. To assess its device-level applicability, we assemble an asymmetric supercapacitor, which achieve specific capacitance of 145.3 F g$^{−1}$ at 1.0 A g$^{−1}$ along with energy density of 52.5 Wh kg$^{−1}$ and power density of 800 W kg$^{−1}$. The assembled device retained 93% of its initial capacitance even after 10,000 cycles confirming its high stability. Furthermore, the nanocomposite exhibits outstanding OER activity, requiring 240 mV overpotential to reach 10 mA cm$^{−2}$ while exhibiting a Tafel slope of 74 mV dec$^{−1}$. ... mehrThe enhanced performance is attributed to improve electrical conductivity and a robust heterojunction architecture that promotes rapid charge transfer. This study establishes CeO$_2$-SnO$_2$@S-C as a promising multifunctional electrode for advanced electrochemical energy-storage and conversion systems.