Pt/MnOx/C Catalysts from Electrolytic Manganese Residue and Oil Sludge for VUV Photocatalytic CO Oxidation: Synergistic Bio-Pretreatment and Polyphenol-Mediated Pt Dispersion

The valorization of hazardous industrial wastes into high-performance catalytic materials presents a compelling route to address both environmental pollution and resource scarcity. This work presents a closed-loop strategy for the fabrication of Pt/MnOx/C composite catalysts using electrolytic manganese residue and oil sludge. The strategy integrates anaerobic co-fermentation with mixed halophilic desulfurizing bacteria and polyphenol-mediated Pt dispersion via blueberry extract. The optimal catalyst achieves an exceptional vacuum ultraviolet photocatalytic carbon monoxide oxidation efficiency of 97.79% at ambient temperature, with an endpoint-derived apparent pseudo-first-order rate constant of 0.128 min−1, outperforming a commercial Pt/Al2O3 reference (2.5 wt% Pt) by a factor of 4.4 in apparent rate constant (equivalent to 1.7-fold in 30 min conversion efficiency) while utilizing less than half the noble metal loading (1.12 wt% Pt). Comprehensive characterization reveals a genuine structural synergy arising from (i) ultrafine Pt0 nanoparticles (2.1 nm) anchored at MnOx–carbon interfaces, (ii) a mixed-valence MnOx matrix (Mn2+/Mn3+ = 1.8:1) with abundant surface oxygen defects (28.3% of the O 1s envelope, an upper bound corroborated by EPR spectroscopy) for reactive oxygen species trapping, and (iii) Nitrogen-doped carbon domains (2.8 atomic percent) that facilitate electron transfer. In situ diffuse reflectance infrared Fourier-transform spectroscopy and kinetic analyses are consistent with a Langmuir–Hinshelwood-type mechanism, where CO is activated on Pt0 and reacts with O2 dissociated at oxygen vacancies under vacuum ultraviolet excitation. This work establishes a sustainable paradigm for transforming industrial wastes into high-value photocatalysts, offering a viable pathway toward low-temperature air purification and circular resource utilization.