Catalytic Hydrogen Production by Janus CuAg Nanostructures

Abstract

Janus nanostructures comprising intimate interfaces can integrate distinct building blocks into a single unit and generate new synergetic effects and desirable functionality through the interfaces. Herein, we report a wet‐chemistry approach mediated by n‐butylamine to directly create heterogeneous CuAg nanoparticles (NPs). Such newly created heterostructures with unique interfaces between the Cu and Ag domains exhibit superior catalytic performance for the water‐gas shift (WGS) reaction to produce hydrogen (H2). By optimizing the composition of the heterogeneous CuAg NPs, the supports, as well as the reaction parameters, the CuAg NPs/ZnO can deliver a TOF value of 673.5 h−1 and a 198.1 μmol yield of H2, significantly outperforming Cu NPs, Ag NPs, mixed Cu/Ag NPs, as well as CuAg NPs without an interface. XPS analysis indicates that the excellent performance is attributed to a unique interface effect, which endows the optimized catalyst with an enhanced antioxidant ability and thus large ratio of metallic Cu. The catalyst also shows outstanding durability with a largely maintained interface and activity after nine runs.

Highly Active and Selective Electrocatalytic CO2 Conversion Enabled by Core/Shell Ag/(Amorphous-Sn(IV)) Nanostructures with Tunable Shell Thickness

“…All characterization methods in this work were described in our previous work. 31,32 Preparation of Working Electrode. To prepare Ag/(A-Sn(IV))/C, 4.3 mg of Ag/(A-Sn(IV)) was first dispersed in 5 mL of cyclohexane under ultrasonication for 3 min, and 15 mg of carbon (VC-X72) was then added into the solution.…”

Self-Limiting Shell Formation in Cu@Ag Core–Shell Nanocrystals during Galvanic Replacement

“…8,18 Cu−Ag bimetallic NCs are chosen here as a model system with a positive Gibbs free energy of mixing. Bimetallic NCs containing these two metals have previously been synthesized as core−shells, 19,20 nanocrescents, 21 and Janus particles 22 in decreasing order of symmetry. Highly symmetric Cu−Ag core−shells (Cu@Ag) have the simplest geometry for investigating the physical principles in formation dynamics.…”

“…From a thermodynamic point of view, formation of core–shell bimetallic structures requires a system with a positive Gibbs free energy of mixing so that nanoscale segregated domains can form instead of an alloy or an intermetallic compound. , Cu–Ag bimetallic NCs are chosen here as a model system with a positive Gibbs free energy of mixing. Bimetallic NCs containing these two metals have previously been synthesized as core–shells, , nanocrescents, and Janus particles in decreasing order of symmetry. Highly symmetric Cu–Ag core–shells (Cu@Ag) have the simplest geometry for investigating the physical principles in formation dynamics.…”

Opportunities and Challenges of Interface Engineering in Bimetallic Nanostructure for Enhanced Electrocatalysis

“…The directly synthesized interfaces are generally prepared by a simple one‐pot reaction, where the different reduction abilities of different metal precursors play the key role ( Table 1 ). Taking advantages of this pathway, the interfaces, such as metal/metal, metal/alloy, and metal/metal compound can be generated . Another interface formed by the directly synthesized method is the support assisted method, which is available for forming highly dispersive bimetals with strong interaction .…”

“…In addition, an interesting interface can be formed in the Janus structure via the direct synthesis method, which is based on the different solid solubility of two metals. For example, due to the limited solid solubility of Ag in Cu, the Cu–Ag Janus NPs with obvious Cu/Ag interface can be obtained by heating the mixture of silver (I) acetate (AgAc), copper (II) acetylacetonate (Cu(acac) 2 ), n ‐butylamine and oleylamine (OAm) at 180 °C for 3 h (Figure d). Wang and Li also report a noble metal–induced reduction method to fabricate the Au/Co(Ni) bimetallic NPs.…”