Low‐Temperature Solid‐State Ion‐Exchange Synthesis Strategy for Cu/SAPO‐34: Effect of Copper Precursors on the Performance of Continuous Direct Conversion of Methane to Methanol

Abstract Three Cu/SAPO‐34 catalysts were synthesized via low‐temperature solid‐state ion‐exchange using CuCl 2 , Cu(NO 3 ) 2 , and Cu(OAc) 2 precursors to investigate precursor effects on continuous direct conversion of methane‐to‐methanol. In the methane‐water‐oxygen continuous flow reaction system at 400 °C, the STY of methanol shows the order of Cu(CuCl 2 )/SAPO‐34 (172.8 µmol/( g cat ·h)) > Cu(Cu(NO 3 ) 2 )/SAPO‐34 (162.7 µmol/( g cat ·h)) > Cu(Cu(OAc) 2 )/SAPO‐34 (139.5 µmol/( g cat ·h)). H 2 ‐TPR, EPR, and variable‐temperature in‐situ DRIFTS revealed that the precursor decomposition temperatures critically regulate copper species migration and distribution. Precursors (CuCl 2 , Cu(NO 3 ) 2 ) rapidly released copper species that occupied SAPO‐34 ion‐exchange sites through solid‐state ion migration, forming abundant isolated Cu 2+ active centers. In contrast, Cu(OAc) 2 delayed copper release, causing partial Cu 2+ failing to access ion‐exchange sites and aggregation into CuO nanoparticles. In situ DRIFTS confirmed isolated Cu 2+ species effectively activate methane C─H bonds to generate methyl intermediates, subsequently converted to methanol under H 2 O‐O 2 co‐feeding conditions. The Cu 2+ →Cu + →Cu 2+ redox cycle facilitated oxidative regeneration of active sites, sustaining catalytic center equilibrium.