Simple synthesis of Pt-Ag/SnO2-C for use as a catalyst of methanol oxidation in alkaline media

Research Progress on Preparation and Electrocatalytic Performance of Tin Dioxide Nanomaterials

In the contemporary era of rapid economic growth, addressing the energy issue constitutes a significant subject. In contrast to traditional fossil energy, fuel cells, through specific transformation routes, can generate more energy and reduce pollution under the same conversion relationship. Direct alcohol fuel cells, as a type of proton exchange membrane fuel cell, exhibit relatively superior performance. During the process of converting chemical energy into electrical energy, the conversion efficiency of the electrode is a crucial aspect of the fuel cell's performance, thereby giving rise to electrode electrocatalysis. Nevertheless, the noble metal catalysts employed in current direct alcohol fuel cells are confronted with issues such as high cost, susceptibility to poisoning, and poor durability. A new approach to these problems is urgently needed. Loading noble metals onto metal oxides has been verified as an effective means. Among them, tin dioxide has attracted the attention of researchers due to its outstanding stability, anti-toxicity, and its positive auxiliary role in electrocatalysis. This article will conduct a review of the research progress in loading noble metals on tin dioxide carriers for the electrocatalytic oxidation of small molecule alcohols from various microstructures and loading methods. Finally, the research on metal dioxide electrocatalysts is prospected.

Valorization of spent double substituted Co-Ni-Zn-Fe LDH wastewater nanoadsorbent as methanol electro-oxidation catalyst

Finding suitable non-expensive electrocatalyst materials for methanol oxidation is a significant challenge. Waste valorization of spent wastewater nanoadsorbents is a promising route toward achieving circular economy guidelines. In this study, the residual of layered double hydroxide (LDH) can be used as an electrocatalyst in direct methanol fuel cells as a novel approach. The Co-Ni-Zn-Fe LDH was prepared by the co-precipitation method followed by the adsorption of methyl orange (MO). Moreover, the spent adsorbent was calcined at different temperatures (200, 400, and 600 °C) to be converted to the corresponding mixed metal oxides (MMO). The prepared samples were characterized using XRD, FTIR, HRTEM, zeta potential, and hydrodynamic size measurements. The spent adsorbent was tested as an electro-catalyst for direct methanol electro-oxidation. The spent LDH/MO adsorbent showed a maximum current density of 6.66 mA/cm² at a 50 mV/s scan rate and a 1 M methanol concentration. The spent MMO/MO adsorbent showed a maximum current density of 8.40 mA/cm² at a 200 °C calcination temperature, 50 mV/s scan rate, and a 3 M methanol concentration. Both samples show reasonable stability over time, as indicated by the chronoamperometric response. Further nanoengineering of used nanoadsorbents could be a promising path to repurposing these wastes as electro-oxidation catalysts.