ZnO/CuO hybrid films synthesized by sequential application of electrochemical and spin coating technique

Zhu

et al. 2022

Angewandte Chemie

It is highly desired yet challenging to steer the CO 2 electroreduction reaction (CO 2 ER) toward ethanol with high selectivity, for which the evolution of reaction intermediates on catalytically active sites holds the key. Herein, we report that K doping in Cu 2 Se nanosheets array on Cu foam serves as a versatile way to tune the interaction between Cu sites and reaction intermediates in CO 2 ER, enabling highly selective production of ethanol. As revealed by characterization and simulation, the electron transfer from K to Se can stabilize Cu I species which facilitate the adsorption of linear *CO L and bridge *CO B intermediates to promote CÀ C coupling during CO 2 ER. As a result, the optimized K 11.2% -Cu 2 Se nanosheets array can catalyze CO 2 ER to ethanol as a single liquid product with high selectivity in a potential area from À 0.6 to À 1.2 V. Notably, it offers a Faradaic efficiency of 70.3 % for ethanol production at À 0.8 V with as is stable for 130 h.

Section: Resultsmentioning

confidence: 78%

Over 70 % Faradaic Efficiency for CO₂ Electroreduction to Ethanol Enabled by Potassium Dopant‐Tuned Interaction between Copper Sites and Intermediates

Zhu

et al. 2022

Angewandte Chemie

“…According to the Mott–Schottky plots, all of the products exhibited p-type semiconductor characteristics, in which the absolute value of the slope was negatively correlated with the carrier density. , The absolute value of the slope of Pt 1.07% NPs-c-MoO 2 /a-Ni(OH) 2 NF was 17.87 (Figure c), lower than those of Pt 0.82% NPs-c-Ni(OH) 2 NSs (22.82) and c-MoO 2 /a-Ni(OH) 2 NF (28.73) but higher than those of Pt 1.11% NPs-c-MoO 2 /c-Ni(OH) 2 NF (17.13) and Pt 5.10% NPs-c-MoO 2 (16.22). Besides, the flat band potential ( E FB ) was obtained by extrapolating the slope in the Mott–Schottky plot to intersect with the x-axis . The E FB of Pt 1.07% NPs-c-MoO 2 /a-Ni(OH) 2 NF was 0.62 V, which was more positive than those of Pt 0.82% NPs-c-Ni(OH) 2 NSs (0.51 V) and c-MoO 2 /a-Ni(OH) 2 NF (0.43 V), but negative than those of Pt 1.11% NPs-c-MoO 2 /c-Ni(OH) 2 NF (0.65 V) and Pt 5.10% NPs-c-MoO 2 NF (0.73 V).…”

Section: Resultsmentioning

confidence: 96%

“…The absolute value of the slope and the E FB of the catalyst revealed its electron transfer dynamics at the interface between the electrode and electrolyte. In general, the lower absolute value of the slope and the higher value of the E FB demonstrated the faster charge transfer rate of the catalyst . Therefore, Pt 1.07% NPs-c-MoO 2 /a-Ni(OH) 2 NF displayed a faster charge transfer rate than those of Pt 0.82% NPs-c-Ni(OH) 2 NSs and c-MoO 2 /a-Ni(OH) 2 NF.…”

Section: Resultsmentioning

confidence: 99%

“…Besides, the flat band potential (E FB ) was obtained by extrapolating the slope in the Mott−Schottky plot to intersect with the x-axis. 56 The E FB of Pt 1.07% NPs-c-MoO 2 /a-Ni(OH) 2 NF was 0.62 V, which was more positive than those of Pt 0.82% NPs-c-Ni(OH) 2 NSs (0.51 V) and c-MoO 2 /a-Ni(OH) 2 NF (0.43 V), but negative than those of Pt 1.11% NPs-c-MoO 2 /c-Ni(OH) 2 NF (0.65 V) and Pt 5.10% NPs-c-MoO 2 NF (0.73 V). The absolute value of the slope and the E FB of the catalyst revealed its electron transfer dynamics at the interface between the electrode and electrolyte.…”

Section: ■ Experimental Sectionmentioning

confidence: 99%

“…In general, the lower absolute value of the slope and the higher value of the E FB demonstrated the faster charge transfer rate of the catalyst. 56 The hydrophilicity of the catalyst is associated with the HER kinetics owing to the effect in the adsorption of the active species on the surface of the catalyst. 58 The contact angle measured after the water droplet instantly dripped to the surface of the catalyst's film can reflect the hydrophilicity of the catalyst.…”

Section: ■ Experimental Sectionmentioning

confidence: 99%

See 2 more Smart Citations

Ultrasmall Pt Nanoparticles-Loaded Crystalline MoO₂/Amorphous Ni(OH)₂ Hybrid Nanofilms with Enhanced Water Dissociation and Sufficient Hydrogen Spillover for Hydrogen Generation

Zhang

ACS Sustainable Chem. Eng.

Sun

et al. 2021

Generating hydrogen via the alkali-water electrocatalytic hydrogen evolution reaction (HER) is a prospective avenue, in which the key point is to construct the electrocatalyst with excellent catalytic behavior. Herein, a Pt nanoparticles-loaded crystalline MoO 2 /amorphous Ni(OH) 2 hybrid nanosheets-composed nanofilm (PtNPs-c-MoO 2 /a-Ni(OH) 2 NF) on Ni foam was designed via a one-step solution-phase strategy for the alkaline HER. The hydrophilic amorphous Ni(OH) 2 in the hybrid nanosheets accelerated water dissociation, and the spillover effect of H atoms from Pt nanoparticles to MoO 2 in the hybrid nanosheets increased the utilization of the dissociated H atoms; moreover, the MoO 2 and the Ni(OH) 2 heterostructure in the hybrid nanosheets exposed copious active edge sites, which jointly enhanced the HER performance of the Pt NPs-c-MoO 2 /a-Ni(OH) 2 NF. The density functional theory (DFT) results showed that the water dissociation at Pt/Ni(OH) 2 (−0.24 eV) is thermodynamically more favored than that on Pt(111) (0.62 eV), and the recombination of one H* on Pt and one H* on MoO 2 could significantly reduce the energy barrier to only 0.05 eV. The optimized Pt 1.07% NPs-c-MoO 2 /a-Ni(OH) 2 NF with ∼2 nm ultrasmall Pt nanoparticles can achieve 10 mA cm −2 at an ultralow overpotential of 18 mV and 500 mA cm −2 at a low overpotential of 167 mV with superior long-term steadiness. Moreover, the mass activity of Pt 1.07% NPs-c-MoO 2 /a-Ni(OH) 2 NF achieved 8.24 mA μg Pt −1 at an overpotential of 70 mV, nearly 21.7-fold that of commercial Pt/C. Our synthesis strategy can be extended to obtain the Pd or Au nanoparticles-loaded c-MoO 2 /a-Ni(OH) 2 nanofilm with low noblemetal content for enhanced HER activities.

Over 70 % Faradaic Efficiency for CO₂ Electroreduction to Ethanol Enabled by Potassium Dopant‐Tuned Interaction between Copper Sites and Intermediates

Zhu

et al. 2022

Angew Chem Int Ed