A Polypyrrole-Modified Pd-Ag Bimetallic Electrode for the Electrocatalytic Reduction of 4-Chlorophenol

A polypyrrole-modified bimetallic electrode composed of Pd-Ag on a Ti substrate (Pd-Ag/PPY/Ti) was successfully prepared via a chemical deposition method, and was applied to the electrocatalytic hydrodechlorination of 4-chlorophenol (4-CP) in aqueous solution. The electrode was characterized by cyclic voltammetry (CV), scanning electron microscopy (SEM), X-ray diffraction (XRD), and X-ray photoelectron spectroscopy (XPS). Various influences on the dechlorination efficiency of 4-chlorophenol, including applied current, initial pH value, and temperature, were studied. The dechlorination efficiency of 4-CP reached 94% within 120 min under the optimum conditions, i.e., a dechlorination current of 6 mA, an initial pH of 2.30, and a temperature of 303 K. The apparent activation energy of the dechlorination of 4-CP by the Pd-Ag/PPY/Ti electrode was calculated to be 49.6 kJ/mol. The equivalent conversion rate constant kPd was 0.63 L.gPd−1·min−1, which was higher than the findings presented in comparable literature. Thus, a highly effective bimetallic electrode with promising application prospects and low Pd loading was fabricated.

Synthesis of Ni3Si4O10(OH)2 Porous Microspheres as Support of Pd Catalyst for Hydrogenation Reaction

Nickel phyllosilicates have attracted much attention owing to their potential applications in various fields. Herein, Ni₃Si₄O₁₀(OH)₂ porous microspheres (NiSi-PMs) with a diameter of 1.2 to 3.2 μm were successfully fabricated via a urea-assisted hydrothermal method, and subsequently used to prepare supported Pd catalyst. Characterizations of the NiSi-PMs and the obtained catalyst, combined with the catalytic performance for the hydrogenation reaction, are presented and discussed. The BET surface area and pore volume of the NiSi-PMs were 196.2 m² g^-1 and 0.70 cm³ g^-1, respectively. The Pd/NiSi-PMs catalyst exhibited remarkable catalytic activity for the hydrogenation of styrene under mild conditions, with a turnover frequency of 5234 h^-1, and the catalyst was recovered and recycled for six consecutive cycles without any discernible loss of activity. H₂-TPR and H₂-TPD revealed that the activity of the catalysts was closely related to the adsorption property for hydrogen. The present Ni₃Si₄O₁₀(OH)₂ supported Pd catalyst afforded a promising and competitive candidate for heterogeneous catalysis.

Rh/polymeric carbon nitride porous tubular catalyst: visible light enhanced chlorophenol hydrodechlorination in base-free aqueous medium

Novel porous tubular Rh/PCN exhibited highly promoted activity in hydrodechlorination of harmful chlorophenols to high-value cyclohexanol and cyclohexanone with base-free aqueous medium and balloon H₂ pressure under the irradiation of visible light.

Palladium Supported on Titanium Carbide: A Highly Efficient, Durable, and Recyclable Bifunctional Catalyst for the Transformation of 4-Chlorophenol and 4-Nitrophenol

Developing highly efficient and recyclable catalysts for the transformation of toxic organic contaminates still remains a challenge. Herein, Titanium Carbide (Ti₃C₂) MXene modified by alkali treatment process was selected as a support (designated as alk-Ti₃C₂X₂, where X represents the surface terminations) for the synthesis of Pd/alk-Ti₃C₂X₂. Results show that the alkali treatment leads to the increase of surface area and surface oxygen-containing groups of Ti₃C₂X₂, thereby facilitating the dispersion and stabilization of Pd species on the surface of alk-Ti₃C₂X₂. The Pd/alk-Ti₃C₂X₂ catalyst shows excellent catalytic activity for the hydrodechlorination of 4-chlorophenol and the hydrogenation of 4-nitrophenol in aqueous solution at 25 °C and hydrogen balloon pressure. High initial reaction rates of 216.6 and 126.3 min⁻¹·gpd−1 are observed for the hydrodechlorination of 4-chlorophenol and hydrogenation of 4-nitrophenol, respectively. Most importantly, Pd/alk-Ti₃C₂X₂ exhibits excellent stability and recyclability in both reactions without any promoters. The superior property of Pd/alk-Ti₃C₂X₂ makes it as a potential material for practical applications.

Catalysis of the hydrodechlorination of 4-chlorophenol and the reduction of 4-nitrophenol by Pd/Fe3O4@C

A recyclable and efficient magnetic core–shell Pd/Fe₃O₄@C nanocatalyst is applied in the HDC of 4-CP and hydrogenation of 4-NP.

Catalysis of the hydro-dechlorination of 4-chlorophenol and the reduction of 4-nitrophenol by Pd/Fe3O4@SiO2@m-SiO2

A Pd/Fe₃O₄@SiO₂@m-SiO₂catalyst with ultrahigh surface area is used in the catalysis of hydrodechlorination of 4-chlorophenol and reduction of 4-nitrophenol.

Palladium encapsulated within magnetic hollow mesoporous TiO2 spheres (Pd/Fe3O4@hTiO2) as a highly efficient and recyclable catalysts for hydrodechlorination of chlorophenols

Herein, we introduced a method to encapsulate Pd(0) within TiO₂ hollow mesoporous nanostructures.