There is an urgent need for cost‐effective strategies to produce hydrogen from renewable net‐zero carbon sources using renewable energies. In this context, the electrochemical hydrogen evolution reaction can be boosted by replacing the oxygen evolution reaction with the oxidation of small organic molecules, such as ethylene glycol (EG). EG is a particularly interesting organic liquid with two hydroxyl groups that can be transformed into a variety of C1 and C2 chemicals, depending on the catalyst and reaction conditions. Here, a catalyst is demonstrated for the selective EG oxidation reaction (EGOR) to formate on nickel selenide. The catalyst nanoparticle (NP) morphology and crystallographic phase are tuned to maximize its performance. The optimized NiS electrocatalyst requires just 1.395 V to drive a current density of 50 mA cm⁻² in 1 m potassium hydroxide (KOH) and 1 m EG. A combination of in situ electrochemical infrared absorption spectroscopy (IRAS) to monitor the electrocatalytic process and ex situ analysis of the electrolyte composition shows the main EGOR product is formate, with a Faradaic efficiency above 80%. Additionally, C2 chemicals such as glycolate and oxalate are detected and quantified as minor products. Density functional theory (DFT) calculations of the reaction process show the glycol‐to‐oxalate pathway to be favored via the glycolate formation, where the CC bond is broken and further electro‐oxidized to formate.

To achieve optimal thermoelectric performance, it is crucial to manipulate the scattering processes within materials to decouple the transport of phonons and electrons. In half-Heusler (hH) compounds, selective defect reduction can significantly improve performance due to the weak electron-acoustic phonon interaction. This study utilized Sb-pressure controlled annealing process to modulate the microstructure and point defects of Nb_0.55Ta_0.40Ti_0.05FeSb compound, resulting in a 100% increase in carrier mobility and a maximum power factor of 78 µW cm⁻¹ K⁻², approaching the theoretical prediction for NbFeSb single crystal. This approach yielded the highest average zT of ~0.86 among hH in the temperature range of 300-873 K. The use of this material led to a 210% enhancement in cooling power density compared to Bi₂Te₃-based devices and a conversion efficiency of 12%. These results demonstrate a promising strategy for optimizing hH materials for near-room-temperature thermoelectric applications.

AgSbTe₂ is a promising p-type thermoelectric material operating in the mid-temperature regime. To further enhance its thermoelectric performance, previous research has mainly focused on reducing lattice thermal conductivity by forming ordered nanoscale domains for instance. However, the relatively low power factor is the main limitation affecting the power density of AgSbTe₂-based thermoelectric devices. In this work, we demonstrate that hole-doped AgSbTe₂ with Sn induces the formation of a new impurity band just above the valence band maximum. This approach significantly improves the electrical transport properties, contrary to previous strategies that focused on reducing lattice thermal conductivity. As a result, we achieve a record-high power factor of 27 μWcm⁻¹K⁻² and a peak thermoelectric figure of merit zT of 2.5 at 673 K. This exceptional performance is attributed to an increased hole concentration resulting from the formation of the impurity band and a lower formation energy of the defect complexes (\({V}_{{Ag}}^{1-}\) + \({{Sn}}_{{Sb}}^{1-}\)). Besides, the doped materials exhibit a significantly improved Seebeck coefficient by inhibiting bipolar conductivity and preventing the formation of n-type Ag₂Te. Additionally, the optimized AgSbTe₂ is used to fabricate a unicouple thermoelectric device that achieves energy conversion efficiencies of up to 12.1% and a high power density of 1.13 Wcm⁻². This study provides critical insights and guidance for optimizing the performance of p-type AgSbTe₂ in thermoelectric applications.