The present study aimed to evaluate the feasibility of developing low-cost N- and Fe-doped TiO₂ photocatalysts for investigating the mineralization of 2,4-dimethylaniline (2,4-DMA). With a single anatase phase, the photocatalysts showed high thermal stability with mass losses of less than 2%. The predominant oxidative state is Ti⁴⁺, but there is presence of Ti³⁺ associated with oxygen vacancies. In materials with N, doping was interstitial in the NH₃/NH⁴⁺ form and for doping with Fe, there was a presence of Fe-Ti bonds (indicating substitutional occupations). With an improved band gap energy from 3.16 eV to 2.82 eV the photoactivity of the photocatalysts was validated with an 18 W UVA lamp (340–415 nm) with a flux of 8.23 × 10⁻⁶ Einstein s⁻¹. With a size of only 14.45 nm and a surface area of 84.73 m² g⁻¹, the photocatalyst doped with 0.0125% Fe mineralized 92% of the 2,4-DMA in just 180 min. While the 3% N photocatalyst with 12.27 nm had similar performance at only 360 min. Factors such as high surface area, mesoporous structure and improved E_bg, and absence of Fe peak in XPS analysis indicate that doping with 0.0125% Fe caused a modification in TiO₂ structure.

Simultaneous hydrogen fuel and value-added chemical production from renewable resources is a key strategy in sustainable catalysis. This work presents a novel strategy employing metal–organic frameworks (MOFs) as precursors for synthesizing advanced titanium dioxide (TiO₂) photocatalysts with enhanced structural and optical properties. Two photocatalysts, M-BDC and M-2,5PDC, were synthesized via controlled calcination of MIL-125(Ti) using terephthalic and 2,5-pyridinedicarboxylic acids, respectively. Characterization confirmed the formation of mixed anatase/rutile TiO₂ phases with mesoporous structures. Notably, nitrogen incorporation in M-2,5PDC reduced the optical band gap to 2.94 eV compared with 3.08 eV for M-BDC, enhancing visible-light absorption. Photocatalytic experiments conducted at near-neutral pH (6.0) demonstrated effective simultaneous glycerol oxidation and hydrogen evolution without the use of alkaline additives. M-BDC achieved 30% glycerol conversion with 78.85% selectivity toward dihydroxyacetone and 21.15% toward glyceraldehyde, while M-2,5PDC exhibited selectivities of 71.55% and 28.45%, respectively. Glycerol underwent partial oxidation without complete mineralization, generating high-value products in parallel with hydrogen production. Both catalysts displayed excellent reuse stability across three consecutive cycles, with M-BDC showing enhanced dihydroxyacetone selectivity (78.85% to 84.42% between cycles). This MOF-derived TiO₂ platform integrates controlled synthesis, near-neutral pH operation, high selectivity, and catalytic stability, thereby establishing a viable strategy for the simultaneous production of clean fuel and value-added chemicals from renewable resources.

Carbon dioxide (CO2) from fossil fuel combustion drives anthropogenic climate change, and electrochemical CO2 reduction reaction (CO2RR) offers a pathway to convert this waste into valuable chemicals. However, catalytic performance is often discussed in terms of active site density alone, while the role of the local interfacial environment remains insufficiently resolved. Here, a series of Printex L6 carbon-supported copper catalysts (PL6C@Cux, where x corresponds to the actual Cu loading wt %) were systematically evaluated for the selective CO2-to-CO conversion. Through linear sweep voltammetry analysis, PL6C@Cu1.04 was identified as the best-performing catalyst among the catalysts investigated; this catalyst exhibited a marked anodic shift in onset potential (to −0.53 V vs RHE) compared to the bare PL6C and nonoptimized loadings. Rotating ring-disk electrode measurements confirmed CO as the dominant product, detected via oxidation at ∼0.8 V vs RHE. To elucidate the mechanistic origins of the enhancement in catalytic efficiency, the interfacial microenvironment was investigated using a quinone redox probe sensitive to local CO2 concentration and adsorption dynamics. The optimized PL6C@Cu1.04 catalyst showed an estimated 15-fold increase in the local CO2 affinity index compared to the bare PL6C catalyst, associated with a 140 mV positive shift in the half-wave potential of the redox probe. This study offers experimental evidence suggesting that optimizing metal loading not only maximizes active sites but also assists in engineering a CO2-enriched microenvironment, which appears crucial for driving efficient and selective electrocatalysis.