Boosting the hydrogen evolution activity of a Co-N-C electrocatalyst by codoping with Al.
Xiao ZhouHaoran YuYang LiuYong KongYongxin TaoYong QinPublished in: RSC advances (2019)
Co, Al and N tri-doped graphene (CANG) was successfully fabricated via annealing N-doped graphene with Co and Al precursors. The material was characterized by scaning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray diffraction (XRD), Raman spectroscopy, physical adsorption, and X-ray photoelectron spectroscopy (XPS). It was found that the as-prepared CANG features a robust three-dimensional hierarchically porous structure. The contents of Co and Al can achieve the maximum value of 2.18 at% and 0.51 at% at the annealing temperature of 950 °C. Upon using the electrocatalyst for the hydrogen evolution reaction (HER), the CANG exhibited remarkable electrocatalytic performance in both acidic ( η 10 = 105 mV) and alkaline media ( η 10 = 270 mV), and outperforms Co,N-codoped graphene and Al,N-codoped graphene, respectively. In combination with the density functional theory (DFT) calculations, it was revealed that the introduction of the Al heteroatom can decrease the absolute value of hydrogen adsorption free energy (Δ G (H*)) of Co-N-C catalysts, thus greatly enhancing the HER activity. This discovery will provide new guidance to the design of advanced and inexpensive carbon materials for fuel cell, water-splitting and other electrochemical devices.
Keyphrases
- electron microscopy
- density functional theory
- metal organic framework
- molecular dynamics
- high resolution
- room temperature
- quantum dots
- single cell
- mental health
- physical activity
- ionic liquid
- gold nanoparticles
- computed tomography
- magnetic resonance imaging
- mass spectrometry
- mesenchymal stem cells
- molecular dynamics simulations
- single molecule
- aqueous solution
- crystal structure
- monte carlo
- anaerobic digestion
- tandem mass spectrometry