(23f) Niobium Doped Molybdenum Disulfide Catalyst for CO2 Reduction Reaction

The world population consumes an average of 15 trillion watts of power, 85% of which comes from burning fossil resources including petroleum, natural gas, coal, and wood.¹ Despite their low cost and high quality, the use of fossil fuels is unavoidably coupled to the release of many compounds such as carbon dioxide (CO₂) that may adversely affect the environment such as acidifying oceans and climate change.^2,3 Thus, controlling CO₂ emission is essential using either renewable energy sources or remediation techniques. Among various remediation techniques, electrochemical reduction of CO₂ is known as the best approach since it not only reduces the amount of existing CO₂ in the atmosphere but also recycle the inert CO₂ molecule into energy-rich products (e.g., syngas). Layered transition metal dichalcogenides (TMDCs) have recently shown a significant potential to use as the catalyst for a wide range of electrochemical energy conversion and storage systems such as hydrogen evolution and CO₂ reduction^4,5. However, it has been always a challenge to tailor the electronic structure of TMDCs to achieve highly promoted catalysts.

In this report, we have discovered a superior catalytic performance of Niobium (Nb) doped vertically aligned MoS₂ (VA-MoS₂) as an energy efficient and highly active catalyst for syngas production. Our results indicate that with only 5% Nb concentration at the edge atom structures, MoS₂ exhibits more than two orders of magnitude higher activity than Ag nanoparticles and one order of magnitude higher than pristine MoS₂ at low overpotentials (-0.2 V vs RHE).⁶ Additionally, the product characterization results reveal that this promoted catalyst is selective for syngas (CO and H₂) formation at the potential range of -0.164 V to -0.764 V vs RHE. The effect of doping on the structure of pristine MoS₂ was studied by synthesis and testing different concentrations of dopant for the CO₂ reduction reaction. Different characterization methods such as scanning transmission electron microscopy (STEM), X-ray photoelectron spectroscopy (XPS), electron energy loss spectra (EELS), energy-dispersive X-ray spectroscopy (EDX) and in-situ differential electrochemical mass spectrometry (DEMS) were applied to fully elucidate the effect of dopant on the electronic structure of MoS₂ and its catalytic activity and selectivity.

 

References:

(1) Davis, S. J.; Caldeira, K.; Matthews, H. D. Future CO2 Emissions and Climate Change from Existing Energy Infrastructure. Science. 2010, 329, 1330â??1333.

(2) Haszeldine, R. S. Carbon Capture and Storage: How Green Can Black Be? Science. 2009, 325, 1647â??1652.

(3) Lastoskie, C. Caging Carbon Dioxide. Science. 2010, 330, 595â??596.

(4) Behranginia, A.; Asadi, M.; Liu, C.; Yasaei, P.; Kumar, B.; Phillips, P.; Foroozan, T.; Waranius, J. C.; Kim, K.; Abiade, J.; et al. Highly Efficient Hydrogen Evolution Reaction Using Crystalline Layered Three-Dimensional Molybdenum Disulfides Grown on Graphene Film. Chem. Mater. 2016, 28, 549â??555.

(5) Asadi, M.; Kumar, B.; Liu, C.; Phillips, P.; Yasaei, P.; Behranginia, A.; Zapol, P.; Klie, R. F.; Curtiss, L. A.; Salehi-Khojin, A. Cathode Based on Molybdenum Disulfide Nanoflakes for Lithiumâ??Oxygen Batteries. ACS Nano, 2016, 10 (2), pp 2167â??2175.

(6) Asadi, M.; Kumar, B.; Behranginia, A.; Rosen, B. a; Baskin, A.; Repnin, N.; Pisasale, D.; Phillips, P.; Zhu, W.; Haasch, R.; et al. Robust Carbon Dioxide Reduction on Molybdenum Disulphide Edges. Nat. Com. 2014, 5, 4470.