A New Eco-friendly Anticorrosion Strategy for Ferrous Metals: Plasma Electrolytic Aluminating

To avoid possible eco-disadvantages of phosphating and zinc plating used for corrosion protection of ferrous metals, this work was to develop an alternative coating technique, called plasma electrolytic aluminating (PEA) process, which can be environmentally friendly in terms of the process itself, and eco-friendly with respect to the coating materials. The PEA process was to form a metal aluminate coating on the metallic surfaces through plasma discharging in an aluminate-based electrolyte when a high voltage was applied to the metals. The aluminating mechanism was investigated using scanning electron microscopy, X-ray photoelectron spectroscopy, and X-ray diffraction (XRD). The research revealed that the hercynite film formed on the metallic surface was indispensable for initiation of the aluminating process. Only after a continuous hercynite film fully covered the metallic surface could the stable plasma discharges be established to sinter the film into a strong ceramic coating. The XRD analysis indicated that a prolonged PEA treatment would result in a hercynite–alumina composite coating. Hardness tests and electrochemical corrosion tests showed that the composite coating could provide the gray cast iron (as an example of ferrous metals) with excellent wear and corrosion protection. With the benign coating process and safe ceramic coating materials, the plasma electrolytic aluminating approach could be used as an eco-friendly and cost-effective strategy for anticorrosion of ferrous metals

Electron Tomography Reveals Porosity Degradation Spatially on Individual Pt-Based Nanocatalysts

Probing porosity evolution is essential to understand the degradation mechanism of electrocatalytic activity. However, spatially dependent degradation pathways for porous catalysts remain elusive. Here, we reveal the multiple degradation behaviors of individual PtCu3 nanocatalysts spatially by three-dimensional (3D) electron tomography. We demonstrate that the surface area–volume ratio (SVR) of cycled porous particles decreases linearly rather than reciprocally with particle size. Additionally, an improved SVR (about 3-fold enhancement) results in increased oxygen reduction reaction (ORR) efficiency at the early stage. However, in the subsequent cycles, the degradation of catalytic activity is due to the excessive growth of pores, the reduction of reaction sites, and the chemical segregation of Cu atoms. The spatial porosity evolution model of nanocatalysts is applicable for a wide range of catalytic reactions, providing a critical insight into the degradation of catalyst activity

Electron Tomography Reveals Porosity Degradation Spatially on Individual Pt-Based Nanocatalysts

Probing porosity evolution is essential to understand the degradation mechanism of electrocatalytic activity. However, spatially dependent degradation pathways for porous catalysts remain elusive. Here, we reveal the multiple degradation behaviors of individual PtCu3 nanocatalysts spatially by three-dimensional (3D) electron tomography. We demonstrate that the surface area–volume ratio (SVR) of cycled porous particles decreases linearly rather than reciprocally with particle size. Additionally, an improved SVR (about 3-fold enhancement) results in increased oxygen reduction reaction (ORR) efficiency at the early stage. However, in the subsequent cycles, the degradation of catalytic activity is due to the excessive growth of pores, the reduction of reaction sites, and the chemical segregation of Cu atoms. The spatial porosity evolution model of nanocatalysts is applicable for a wide range of catalytic reactions, providing a critical insight into the degradation of catalyst activity

Electron Tomography Reveals Porosity Degradation Spatially on Individual Pt-Based Nanocatalysts

Probing porosity evolution is essential to understand the degradation mechanism of electrocatalytic activity. However, spatially dependent degradation pathways for porous catalysts remain elusive. Here, we reveal the multiple degradation behaviors of individual PtCu3 nanocatalysts spatially by three-dimensional (3D) electron tomography. We demonstrate that the surface area–volume ratio (SVR) of cycled porous particles decreases linearly rather than reciprocally with particle size. Additionally, an improved SVR (about 3-fold enhancement) results in increased oxygen reduction reaction (ORR) efficiency at the early stage. However, in the subsequent cycles, the degradation of catalytic activity is due to the excessive growth of pores, the reduction of reaction sites, and the chemical segregation of Cu atoms. The spatial porosity evolution model of nanocatalysts is applicable for a wide range of catalytic reactions, providing a critical insight into the degradation of catalyst activity

Electron Tomography Reveals Porosity Degradation Spatially on Individual Pt-Based Nanocatalysts

Probing porosity evolution is essential to understand the degradation mechanism of electrocatalytic activity. However, spatially dependent degradation pathways for porous catalysts remain elusive. Here, we reveal the multiple degradation behaviors of individual PtCu3 nanocatalysts spatially by three-dimensional (3D) electron tomography. We demonstrate that the surface area–volume ratio (SVR) of cycled porous particles decreases linearly rather than reciprocally with particle size. Additionally, an improved SVR (about 3-fold enhancement) results in increased oxygen reduction reaction (ORR) efficiency at the early stage. However, in the subsequent cycles, the degradation of catalytic activity is due to the excessive growth of pores, the reduction of reaction sites, and the chemical segregation of Cu atoms. The spatial porosity evolution model of nanocatalysts is applicable for a wide range of catalytic reactions, providing a critical insight into the degradation of catalyst activity

Electron Tomography Reveals Porosity Degradation Spatially on Individual Pt-Based Nanocatalysts

Probing porosity evolution is essential to understand the degradation mechanism of electrocatalytic activity. However, spatially dependent degradation pathways for porous catalysts remain elusive. Here, we reveal the multiple degradation behaviors of individual PtCu3 nanocatalysts spatially by three-dimensional (3D) electron tomography. We demonstrate that the surface area–volume ratio (SVR) of cycled porous particles decreases linearly rather than reciprocally with particle size. Additionally, an improved SVR (about 3-fold enhancement) results in increased oxygen reduction reaction (ORR) efficiency at the early stage. However, in the subsequent cycles, the degradation of catalytic activity is due to the excessive growth of pores, the reduction of reaction sites, and the chemical segregation of Cu atoms. The spatial porosity evolution model of nanocatalysts is applicable for a wide range of catalytic reactions, providing a critical insight into the degradation of catalyst activity

Electron Tomography Reveals Porosity Degradation Spatially on Individual Pt-Based Nanocatalysts

Probing porosity evolution is essential to understand the degradation mechanism of electrocatalytic activity. However, spatially dependent degradation pathways for porous catalysts remain elusive. Here, we reveal the multiple degradation behaviors of individual PtCu3 nanocatalysts spatially by three-dimensional (3D) electron tomography. We demonstrate that the surface area–volume ratio (SVR) of cycled porous particles decreases linearly rather than reciprocally with particle size. Additionally, an improved SVR (about 3-fold enhancement) results in increased oxygen reduction reaction (ORR) efficiency at the early stage. However, in the subsequent cycles, the degradation of catalytic activity is due to the excessive growth of pores, the reduction of reaction sites, and the chemical segregation of Cu atoms. The spatial porosity evolution model of nanocatalysts is applicable for a wide range of catalytic reactions, providing a critical insight into the degradation of catalyst activity

Electron Tomography Reveals Porosity Degradation Spatially on Individual Pt-Based Nanocatalysts

Probing porosity evolution is essential to understand the degradation mechanism of electrocatalytic activity. However, spatially dependent degradation pathways for porous catalysts remain elusive. Here, we reveal the multiple degradation behaviors of individual PtCu3 nanocatalysts spatially by three-dimensional (3D) electron tomography. We demonstrate that the surface area–volume ratio (SVR) of cycled porous particles decreases linearly rather than reciprocally with particle size. Additionally, an improved SVR (about 3-fold enhancement) results in increased oxygen reduction reaction (ORR) efficiency at the early stage. However, in the subsequent cycles, the degradation of catalytic activity is due to the excessive growth of pores, the reduction of reaction sites, and the chemical segregation of Cu atoms. The spatial porosity evolution model of nanocatalysts is applicable for a wide range of catalytic reactions, providing a critical insight into the degradation of catalyst activity

Electron Tomography Reveals Porosity Degradation Spatially on Individual Pt-Based Nanocatalysts

Probing porosity evolution is essential to understand the degradation mechanism of electrocatalytic activity. However, spatially dependent degradation pathways for porous catalysts remain elusive. Here, we reveal the multiple degradation behaviors of individual PtCu3 nanocatalysts spatially by three-dimensional (3D) electron tomography. We demonstrate that the surface area–volume ratio (SVR) of cycled porous particles decreases linearly rather than reciprocally with particle size. Additionally, an improved SVR (about 3-fold enhancement) results in increased oxygen reduction reaction (ORR) efficiency at the early stage. However, in the subsequent cycles, the degradation of catalytic activity is due to the excessive growth of pores, the reduction of reaction sites, and the chemical segregation of Cu atoms. The spatial porosity evolution model of nanocatalysts is applicable for a wide range of catalytic reactions, providing a critical insight into the degradation of catalyst activity

Electron Tomography Reveals Porosity Degradation Spatially on Individual Pt-Based Nanocatalysts

Probing porosity evolution is essential to understand the degradation mechanism of electrocatalytic activity. However, spatially dependent degradation pathways for porous catalysts remain elusive. Here, we reveal the multiple degradation behaviors of individual PtCu3 nanocatalysts spatially by three-dimensional (3D) electron tomography. We demonstrate that the surface area–volume ratio (SVR) of cycled porous particles decreases linearly rather than reciprocally with particle size. Additionally, an improved SVR (about 3-fold enhancement) results in increased oxygen reduction reaction (ORR) efficiency at the early stage. However, in the subsequent cycles, the degradation of catalytic activity is due to the excessive growth of pores, the reduction of reaction sites, and the chemical segregation of Cu atoms. The spatial porosity evolution model of nanocatalysts is applicable for a wide range of catalytic reactions, providing a critical insight into the degradation of catalyst activity