Development of photoanodes for photoelectrocatalytic solar cells based on copper-based nanoparticles on titania thin films of vertically aligned nanotubes

Synergistic effects of light and plasma catalysis on Au-modified TiO2 nanotube arrays for enhanced non-oxidative coupling of methane

The direct conversion of methane into value-added hydrocarbons represents one of the most energetically efficient pathways to shift industrial processes towards more sustainable low-carbon technologies. In this study, we present a novel planar dielectric barrier discharge (DBD) reactor equipped with a quartz window for catalyst illumination, to explore potential synergies between light and plasma in the catalytic non-oxidative coupling of methane (NOCM) reaction. Highly ordered TiO2 nanotube arrays were grown on a Ti mesh and further modified with Au nanoparticles to improve light absorption and reactivity, thereby acting as the DBD electrode and NOCM catalyst. The introduction of gold significantly enhances performances, achieving a substantial rise of 64% in plasma-assisted methane conversion compared to the bare support while shifting the selectivity towards alkanes and C3+ hydrocarbons. For the first time, we demonstrated the effect of light irradiation and its interaction with plasma, revealing an effective synergistic mechanism between plasma and light in gold-modified materials. Notably, a 21.5% increase in the intrinsic rate of the NOCM surface process under irradiation was achieved. This improvement is attributed to two factors: induced physical changes in the nature of the plasma micro-discharges and the creation of specific surface vibrational states on the catalyst.

Evaluation of photocatalytic fuel cell (PFC) for electricity production and simultaneous degradation of methyl green in synthetic and real greywater effluents

Recycling of alternative water sources particularly greywater and recovery of energy from wastewater are gaining momentum due to clean water scarcity and energy crisis. In this study, the photocatalytic fuel cell (PFC) employing ZnO/Zn photoanode and CuO/Cu photocathode was successfully designed for effective greywater recycling as well as energy recovery. The photoelectrodes were analyzed using X-ray diffraction (XRD), field-emission scanning electron microscopy (FESEM), energy dispersive X-ray (EDX) and fourier transform infrared (FTIR) spectroscopy. The PFC performance in terms of electricity generation and parallel methyl green (MG) degradation were evaluated under operating parameters such as electrolyte type, initial MG concentration and solution pH. The results showed that the addition of Na₂SO₄ electrolyte, MG concentration of 40 mg L^-1 and solution pH of 5.2 improved the short circuit current density (J_sc) and power density (P_max) in the as-constructed PFC. Such a system also afforded highest MG and chemical oxygen demand (COD) removal efficiencies after 4 h of irradiation. The photoanodes used in this study demonstrated great recyclability after four repetition tests. The COD removal was reduced to some extents when the PFC treatment was tested in the real greywater under optimal conditions. Various greywater quality parameters including ammoniacal nitrogen (NH₃-N), turbidity, pH and biochemical oxygen demand (BOD₅) were also monitored. The phytotoxicity experiments via Vigna radiate seeds indicated a reduction in the phytotoxicity.