RESUMEN
Utilizing photocatalytic CO2 reduction presents a promising avenue for combating climate change and curbing greenhouse gas emissions. However, maximizing its potential hinges on the development of materials that not only enhance efficiency but also ensure process stability. Here, we introduce Hiroshima University Silicate-7 (HUS-7) with immobilized Ti species as a standout contender. Our study demonstrates the remarkable photocatalytic activity of HUS-7 in CO2 reduction, yielding substantially higher carbonaceous product yields compared to conventional titanium-based catalysts TS-1 and P25. Through thorough characterization, we elucidate that their boosted photocatalytic performance is attributed to the incorporation of isolated Ti species within the silica-based precursor, serving as potent photoinduced active sites. Moreover, our findings underscore the crucial role of the Ligand-to-Metal Charge Transfer (LMCT) process in facilitating the photoactivation of CO2 molecules, shedding new light on key mechanisms underlying photocatalytic CO2 reduction.
RESUMEN
In recent years, transportation-related air pollution has escalated into a global concern, necessitating the development of a three-way catalyst (TWC) technology to address harmful emissions. However, the efficiency of TWC's performance in mitigating these emissions has been hindered because of limited mass transfer efficiency within their structures. Thus, this study attempted to overcome the existing issue by synthesizing a series of macroporous TWC particles exhibiting various macropore sizes via a template-assisted spray process, aiming to achieve optimal mass transfer efficiency and catalytic performance. The synthesis incorporated various template particles (size of 67-381 nm) to obtain various macroporous structures. Thereafter, these macroporous particles were assessed for their carbon monoxide (CO) oxidation performance, revealing a substantial influence of the macropore size on the catalytic performance of TWC structures. Interestingly, among the investigated samples, those containing the smallest and largest macropores demonstrated the highest CO oxidation performances. Based on these results, a plausible reactant diffusion mechanism was proposed to explain the effect of the macropore size on the diffusion efficiency within the macroporous structures. This work may have significant implications in optimizing the macroporous structure to enhance catalytic performance in the gas purification process.
RESUMEN
Nowadays, trends in wastewater treatment by zero-valent iron (ZVI) were turned to use bimetallic NZVI particles by planting another metal onto the ZVI surface to increase its reactivity. Nano size zero-valent iron/copper (NZVI/Cu0) bimetallic particles were synthesized in order to examine its toxicity effects on the wastewater microbial life, kinetics of phosphorus, ammonia stripping and the reduction of chemical oxygen demand (COD). Various concentrations of NZVI/Cu0 and operation conditions both aerobic and anaerobic were investigated and compared with pure NZVI experiment. The results showed that addition 10mg/L of NZVI/Cu0 significantly increased the numbers of bacteria colonies under anaerobic condition, conversely it inhibited bacteria activity with the presence of oxygen. Furthermore, the impact of nanoparticles on ammonia stripping and phosphorus removal was also linked to the emitted iron ions electrons. It was found that dosing high concentration of bimetallic NZVI/Cu0 has a negative effect on ammonia stripping regardless of the aeration condition. In comparison to control, dosing only 10mg/L NZVI/Cu0, the phosphorus removal increased sharply both under aerobic and anaerobic conditions, these outcomes were obtained as a result of complete dissolution of bimetallic nanoparticles which formed copper-iron oxides components that are attributed to increasing the phosphorus adsorption rate.
