A Ta-TaS2 monolith catalyst with robust and metallic interface for superior hydrogen evolution

The use of highly-active and robust catalysts is crucial for producing green hydrogen by water electrolysis as we strive to achieve global carbon neutrality. Noble metals like platinum are currently used catalysts in industry for the hydrogen evolution, but suffer from scarcity, high price and unsatisfied performance and stability at large current density, restrict their large-scale implementations. Here we report the synthesis of a type of monolith catalyst consisting of a metal disulfide (e.g., tantalum sulfides) vertically bonded to a conductive substrate of the same metal tantalum by strong covalent bonds. These features give the monolith catalyst a mechanically-robust and electrically near-zero-resistance interface, leading to an excellent hydrogen evolution performance including rapid charge transfer and excellent durability, together with a low overpotential of 398 mV to achieve a current density of 2,000 mA cm−2 as required by industry. The monolith catalyst has a negligible performance decay after 200 h operation at large current densities. In light of its robust and metallic interface and the various choices of metals giving the same structure, such monolith materials would have broad uses besides catalysis.

Effect of the Properties of Cordierite Support and Catalyst Slurry on the Catalytic Degradation of Toluene by Monolith Catalyst

Monolithic catalysts are widely used in industrial catalysis. However, in the preparation of monolithic catalyst, the most important catalyst coating has the problems of low upload rate and poor uniformity. In the present work, the effects of acid treatment of carrier on the upload rate and the effects of size of slurry and dispersant on the uniformity of coating were investigated. The weight loss rate and water absorption rate of cordierite, slurry stability, coating upload rate and catalytic performance were also tested. Characterization analysis was carried out by means of BET, SEM, Zeta potential, the laser grain-size analyzer. The results showed that the optimal performance of cordierite carrier could be obtained by heating the cordierite carrier with 20% HCl for 3 h; the water absorption rate could increase for more than 48.0%, and the upload rate could reach 14.5%. Pearson test showed that there was a moderate positive correlation between water absorption rate and upload rate. It was also found that reducing the particle size of the slurry (1.47 microns) and adding 4% dispersant PAA could effectively improve the stability of the suspension and the uniformity of the coating. When 20% HCl was used to pretreat, the toluene catalytic activity of the monolith catalyst prepared by cordierite increased, in which T10 and T90 both increased for about 5 ℃. At the same time, reducing particle size and adding dispersant could also promote the catalytic degradation efficiency to a certain extent.