Enhancing the stability and electrocatalytic activity of Ti-based PbO2 anodes by introduction of an arc-sprayed TiN interlayer

Performance Enhancement of Ti/IrO2-Ta2O5 Anode through Introduction of Tantalum-Titanium Interlayer via Double-Glow Plasma Surface Alloying Technology

Ti/IrO2-Ta2O5 electrodes are extensively utilized in the electrochemical industries such as copper foil production, cathodic protection, and wastewater treatment. However, their performance degrades rapidly under high current densities and severe oxygen evolution conditions. To address this issue, we have developed a composite anode of Ti/Ta-Ti/IrO2-Ta2O5 with a Ta-Ti alloy interlayer deposited on a Ti substrate by double-glow plasma surface alloying, and the IrO2-Ta2O5 surface coating prepared by the traditional thermal decomposition method. This investigation indicates that the electrode with Ta-Ti alloy interlayer reduces the agglomerates of precipitated IrO2 nanoparticles and refines the grain size of IrO2, thereby increasing the number of active sites and enhancing the electrocatalytic activity. Accelerated lifetime tests demonstrate that the Ti/Ta-Ti/IrO2-Ta2O5 electrode exhibits a much higher stability than the Ti/IrO2-Ta2O5 electrode. The significant improvement in electrochemical stability is attributed to the Ta-Ti interlayer, which offers high corrosion resistance and effective protection for the titanium substrate.

Constant current-exponential attenuation mode: A non-traditional power supply mode for electrocatalytic oxidation

Low average current efficiency (ACE) and high energy consumption (EC) have seriously hindered the industrial development of electrocatalytic oxidation (ECO) technology. Timely adjustment of the current output according to the attenuation law of the organic pollutants concentration during the reaction process can help to solve the low electrical energy utilization problem at source. In this study, a non-traditional power supply mode with "constant current-exponential attenuation" (Mode CC-EA) was proposed and applied to intermittent ECO systems. The current is first output in a constant state and then attenuated exponentially according to the decreasing law of pollutants concentration, enabling efficient use of electrons at all stages of the reaction, resulting in increased degradation rates and ACE, and reduced EC. Acidic red G (ARG) was used as the target pollutant and the degradation effects of the traditional constant current mode (Mode CC), the direct exponential attenuation mode (Mode EA) and the Mode CC-EA were compared with different evaluation parameters. The results showed that the optimized Mode EA (n₄) and Mode CC-EA (70-n₁₁) degraded ARG with an ACE of 5.28 and 6.09%, respectively, which were 1.26 and 1.45 times higher than Mode CC (4.2%). At the same time, the EC were 0.36 and 0.27 kWh gCOD^-1, respectively, which were 12.2 and 34.2% lower than Mode CC (0.41 kWh gCOD^-1). The parameters of Mode CC-EA were further optimized and used for the degradation of three typical dye wastewaters, crystal violet (CV), methylene blue (MB) and methyl orange (MO), to investigate their general applicability. The results showed that the optimized Mode CC-EA achieved higher decolorization rates, chemical oxygen demand (COD) and total organic carbon (TOC) removal rates for the four wastewaters, including ARG, than Mode CC within 120 min for the same total input charge. The ACE of Mode CC-EA was on average 1.3 times higher than that of Mode CC, while the EC was on average 25.3% lower. Mode CC-EA achieves efficient use of electrical energy while ensuring the catalytic effect, which is of great application for the efficient treatment of dye wastewater and significance for the industrial development of ECO technology.

When MXene (Ti3C2Tx) meet Ti/PbO2: An improved electrocatalytic activity and stability

Stable electrode materials with high catalytic activity are urgently required for electrochemical degradation of refractory organic pollutants in wastewater treatment. Herein, high conductive MXene (Ti₃C₂T_x) was firstly fabricated by electrophoretic deposition (EPD) as an interlayer for preparing a novel PbO₂ electrode. The well-conducted Ti₃C₂T_x interlayer significantly improved the electrochemical performance of the EPD-2.0/PbO₂ (EPD time was 2.0 min) electrode with the charge transfer resistance decreased by 9.51 times, the inner active sites increased by 5.21 times and the ∙OH radicals generation ability enhanced by 4.07 times than the control EPD-0/PbO₂ anode. Consequently, the EPD-2.0/PbO₂ electrode achieved nearly 100% basic fuchsin (BF) and 86.78% COD removal efficiency after 3.0 h electrolysis. Therefore, this new PbO₂ electrode presented a promising potential for electrochemical degradation of BF and the new Ti₃C₂T_x middle layer could also be used to fabricate other efficient and stable anodes, such as SnO₂, MnO₂, TiO₂, etc.