Home Green Energy Black gold-nickel catalyst for solar CO2 hydrogenation via hot-electron mechanism: TIFR study

Black gold-nickel catalyst for solar CO2 hydrogenation via hot-electron mechanism: TIFR study

Black gold-nickel catalyst for solar CO2 hydrogenation via hot-electron mechanism: TIFR study

Scientists have found a new way to turn CO2 into a useful fuel source using a plasmonic catalyst. The research titled, “Nickel-Laden Dendritic Plasmonic Colloidosomes of Black Gold: Forced Plasmon Mediated Photocatalytic CO2 Hydrogenation,” published in the journal ACS Nano, presents a new approach to turn CO2 into a fuel source at room temperature using a plasmonic catalyst.

The researchers designed dendritic plasmonic colloidosomes of black gold loaded with nickel sites to catalyze the CO2 hydrogenation reaction mechanism using finite-difference time-domain simulations, light-intensity-dependent production rate, light-intensity-dependent photocatalytic quantum efficiencies, wavelength-dependent production rate, kinetic isotope effect, ultrafast transient absorption spectroscopy, and in situ diffuse reflectance infrared Fourier transform spectroscopy.

Here are the outcomes of the research:

  • Plasmonic black gold-nickel efficiently catalyzes CO2 hydrogenation using visible light.
  • The reaction took place at temperatures as low as 84–223 °C without external heating.
  • DPC-C4-Ni showed the best-reported CO production rate of 2464 ± 40 mmol gNi–1 h–1 and a selectivity greater than 95% under the flow conditions.
  • The catalyst showed extraordinary stability (100 h).
  • The kinetic isotope effect (KIE) in the light (1.91) was higher than that in the dark (∼1), confirming the hot-electron-mediated reaction mechanism.
  • Ultrafast studies of hot-carrier dynamics proved the superfast electron injection from Au to Ni, populating the Ni reactor with charge carriers.
  • The catalyst exhibited a spectral signature of such an indirect charge generation due to hot-electron transfer from the gold to the nickel.
  • Finite-difference time-domain simulations also showed plasmon-induced high local field intensity enhancement in DPC-C4-Ni.
  • CO2 hydrogenation took place by a direct dissociation path via linearly bonded nickel–CO, and the linearly bonded CO on Ni sites of DPC-C4-Ni were weakly bonded due to its weak Ni–C bond.

This study may lead to the development of a sustainable CO2 hydrogenation path and help in the development of technologies to reduce greenhouse gas emissions. The research opens up new possibilities for scientists and policymakers to reduce carbon emissions and mitigate climate change.

Nickel-Laden Dendritic Plasmonic Colloidosomes of Black Gold: Forced Plasmon Mediated Photocatalytic CO2 Hydrogenation

Verma; Belgamwar; Chatterjee; Bericat-Vadell; Sa; Polshettiwar 

Full-text link: https://doi.org/10.1021/acsnano.2c10470

What this paper is about

  • High-temperature reaction be catalyzed at room to moderate temperature via plasmonic excitation of H 2 and CO 2 using a plasmonic catalyst.
  • In this work, dendritic plasmonic colloidosomes of Au loaded with nickel sites, prepared by loading four cycles of Au NPs on dendritic fibrous nanosilica.
  • The CO 2 hydrogenation reaction mechanism was studied by using finite-difference time-domain simulations, light-intensity-dependent production rate, light-intensity-dependent photocatalytic quantum efficiencies, wavelength-dependent production rate, kinetic isotope effect, ultrafast transient absorption spectroscopy, and in situ diffuse reflectance infrared Fourier transform spectroscopy.

What you can learn

  • Ni with two bands centered at 2022 and 1976 cm 1 assigned to CO molecules adsorbed on Ni 0 ultrasmall nanoparticles with linear and bridge orientations, respectively. This indicated the stronger binding of CO on active Ni sites as compared to Au sites in the presence of light.
  • Ni showed no activity in light at 183C, while at 223C, a small amount of CO and methane was formed. This further indicated the role of plasmonic DPC-C4 in activating Ni sites.
  • To further confirm the role of hot electrons, experiments were carried out to study the kinetic isotope effect of photocatalytic CO 2 hydrogenation using 13 CO 2 and 12 CO 2 in light and dark.
  • The activity of all these catalysts was very low, with less than 100 mol g 1 h 1 productivity of total products, 17,8487 as compared to 2464 40 mmol g Ni 1 h 1 for DPC-C4. This indicates that generating hydrogen from water separately and then reacting the produced green hydrogen with CO 2 using a plasmonic photocatalyst is a more sustainable CO 2 hydrogenation path.
  • We found a multifold increase in the catalytic activity as compared to DPC-C4 to the extent that measurable photoactivity was only observed with DPC-C4.
  • Due to the excitation of electrons in the nickel d-band to a higher energy level during plasmonic damping of black gold SPR, as well as to filling of Ni d-band due to hot electron transfer from black gold to Ni.

Core Q&A related to this research

What is the main focus of the paper “Nickel-Laden Dendritic Plasmonic Colloidosomes of Black Gold: Forced Plasmon Mediated Photocatalytic CO2 Hydrogenation”?

The paper focuses on the synthesis of dendritic plasmonic colloidosomes of black gold loaded with nickel sites (DPC-C4-Ni) and their use as a photocatalyst for the hydrogenation of CO2. The study investigates the role of plasmonic excitation of H2 and CO2 using the plasmonic catalyst in high-temperature reactions that can be catalyzed at room to moderate temperature. The reaction mechanism of CO2 hydrogenation is studied using various techniques, including finite-difference time-domain simulations, light-intensity-dependent production rate, and kinetic isotope effect. The authors also compare the performance of DPC-C4-Ni with other reported CO2 hydrogenation catalysts.

What are dendritic plasmonic colloidosomes (DPC-C4-Ni)?

Dendritic plasmonic colloidosomes (DPC-C4-Ni) are a type of catalyst that is synthesized by loading Au nanoparticles onto a dendrited fibrous nanosilica, and then loading nickel sites on top of that. The resulting catalyst has excellent light-harvesting ability and is highly dispersed, providing a weakly bonded CO pathway that leads to high selectivity and production rates for CO2 hydrogenation reactions.

What analytical techniques were used to characterize the DPC-C4-Ni catalyst?

The DPC-C4-Ni catalyst was characterized using a variety of analytical techniques, including X-ray diffraction (XRD), scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FT-IR), and UV-Vis diffuse reflectance (IR) studies. These techniques were used to understand the structure and properties of the catalyst.

What was the catalytic behavior of the DPC-C4-Ni catalyst compared to other CO2 hydrogenation catalysts?

The DPC-C4-Ni catalyst showed a multifold increase in catalytic activity compared to other CO2 hydrogenation catalysts. It produced the best-reported CO production rate of 2464 ± 40 mmol gNi–1 h–1 and a selectivity greater than 95% under flow conditions. In addition, the catalyst showed extraordinary stability over 100 hours.

What is the photocatalytic reaction mechanism of the DPC-C4-Ni catalyst?

The photocatalytic reaction mechanism of the DPC-C4-Ni catalyst was studied using several techniques, including finite-difference time-domain simulations, light-intensity-dependent production rate, and quantum efficiencies. The results showed a superlinear power-law dependence on light intensity and an increase in quantum efficiencies with an increase in light intensity and reaction temperature. The kinetic isotope effect (KIE) in the light was higher than that in the dark, confirming the hot-electron-mediated reaction mechanism.

What is the role of nickel in the CO2 hydrogenation process?

Nickel plays a crucial role in the CO2 hydrogenation process. An in situ DRIFTS study showed that CO2 hydrogenation took place by a direct dissociation path via linearly bonded nickel-CO. The weakly bonded CO on Ni sites of DPC-C4-Ni was due to its weak Ni-C bond, which made CO desorption efficient, restricting hydrogenation to methane and leading to more than 95% CO selectivity. The high production rate and selectivity were due to the highly dispersed Ni NPs on black gold, providing a weakly bonded CO pathway.

Basics details related to this research

Dendritic: Refers to a branched or tree-like structure.

Plasmonic: Related to the interaction of light with metal nanoparticles, where the metal particles can absorb and scatter light in a unique way.

Colloidosomes: Microscopic particles made up of colloidal materials, typically surrounded by a membrane or shell.

Fibrous: Refers to a material or structure that is made up of thin, thread-like fibers.

Nanosilica: Refers to silica nanoparticles, which are composed of silicon dioxide and can be used in a variety of applications.

Catalyst: A substance that increases the rate of a chemical reaction without being consumed in the reaction itself.

X-ray diffraction: A technique used to analyze the crystal structure of a material by shining X-rays on it and measuring the resulting diffraction pattern.

Scanning electron microscopy: A microscopy technique used to image the surface of a material at high magnification.

Fourier transform infrared spectroscopy: A technique used to analyze the vibrational properties of a material by shining infrared light on it and measuring the resulting absorption spectrum.

UV-Vis diffuse reflectance: A technique used to measure the reflectance of a material across a range of wavelengths, typically in the ultraviolet and visible regions of the electromagnetic spectrum.

Photocatalytic: Refers to a chemical reaction that is driven by the absorption of light.

Reaction mechanism: The sequence of steps that occur in a chemical reaction.

Finite-difference time-domain simulations: A computer simulation technique used to model electromagnetic fields and the interactions between materials.

Light-intensity-dependent production rate: The rate at which a chemical product is produced in response to the intensity of light used in a photocatalytic reaction.

Quantum efficiencies: The efficiency with which a material can convert absorbed light into chemical products.

Kinetic isotope effect: The difference in reaction rate between isotopes of a chemical element due to differences in their mass.

Ultrafast transient absorption spectra: A technique used to study the excited-state dynamics of a material by measuring the absorption of light at very short time intervals.

CO2 hydrogenation: The chemical reaction that converts carbon dioxide (CO2) into a more useful product, such as methane (CH4).

Sacrificial agents: Chemicals used in a photocatalytic reaction to supply electrons or protons that are needed to drive the reaction forward.

CO production rate: The rate at which carbon monoxide (CO) is produced in a photocatalytic reaction.

Selectivity: The extent to which a chemical reaction produces only the desired product, without producing unwanted byproducts.

Stability: The ability of a material to maintain its physical and chemical properties over time.

Power-law dependence: A relationship between two variables where one variable changes as a power of the other variable.

Hot-electron-mediated reaction mechanism: A reaction mechanism in which hot electrons, or high-energy electrons generated by the absorption of light, are involved in the chemical reaction.

In situ DRIFTS study: A spectroscopic technique used to study the surface chemistry of a material under reaction conditions.

C═O stretching vibrations: Vibrational modes of the chemical bond between carbon and oxygen in a carbonyl group.

Linearly bonded CO: Refers to a carbon monoxide molecule that is bonded to a metal surface in a linear geometry.

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