Ultralow-Content PdCu Disordered Nanoalloys on Carbon Nitrides for Unity-Selective CO₂ Hydrogenation to Methanol

Catalytic CO₂ hydrogenation to methanol offers a dual benefit of mitigating CO₂ emissions and producing liquid fuel. Herein, we demonstrate an efficient CO₂-to-methanol catalyst (PdCu/PCN), consisting of ultrafine PdCu disordered nanoalloys anchored on polymeric carbon nitride (PCN) nanosheets. Prepared via a facile one-pot co-polymerization recipe, this strategy permits the in situ formation and integration of PdCu alloys during PCN synthesis, which ensures strong interfacial confinement and prevents the generation of oxide-derived encapsulation overlayers, maximizing the exposure of active metal sites. Despite its ultralow metal loading (Pd: 0.18%, Cu: 0.16%), the catalyst achieves a high methanol production rate of 21.24 mmol g_metal ^-1 h^-1 with 100% selectivity at 160 °C, together with outstanding reusability. Alloying Cu with Pd in a disordered nanoalloy structure modulates the CO₂ hydrogenation pathway toward methanol while lowering the energy barrier of the rate-determining step. This work highlights the potential of PCN as a flexible metal-free support for constructing active and durable catalysts for selective CO₂ conversion through in situ alloy engineering.