Catalyst channels with anisotropic structures by 3-d printing

Abstract

A three-dimensional non-noble-metal-based electrocatalysis electrode structure is provided. The electrode structure includes one or more layers of fused and approximately aligned elongated electrocatalyst nanoparticles that include a non-noble metal alloy or non-noble metal compound. Anisotropic nanochannels are positioned between the fused and approximately aligned elongated electrocatalyst nanoparticles that are configured to transfer generated gas bubbles therethrough. The elongated electrocatalyst nanoparticles may be nanorods that may have a diameter of approximately 20 to 50 nanometers and a length of approximately 80 to 300 nanometers. The anisotropic nanochannels may have a channel width of approximately 50-150 nanometers. The non-noble metal may be one or more of iron, cobalt, nickel, copper, molybdenum, or tungsten. The one or more layers of fused and approximately aligned elongated electrocatalyst nanoparticles may be 3-D printed elongated electrocatalyst nanoparticles, and each layer has a thickness of approximately 50 to 200 microns.

1 . A three-dimensional non-noble-metal-based electrocatalysis electrode structure comprising:
 one or more layers of fused and approximately aligned elongated electrocatalyst nanoparticles, the electrocatalyst nanoparticles comprising a non-noble metal alloy or non-noble metal compound;   anisotropic nanochannels positioned between the fused and approximately aligned elongated electrocatalyst nanoparticles configured to transfer generated gas bubbles therethrough.   
     
     
         2 . The three-dimensional non-noble-metal-based electrocatalysis electrode structure of  claim 1 , wherein the elongated electrocatalyst nanoparticles are nanorods. 
     
     
         3 . The three-dimensional non-noble-metal-based electrocatalysis electrode structure of  claim 2 , wherein the nanorods have a diameter of approximately 20 to 50 nanometers. 
     
     
         4 . The three-dimensional non-noble-metal-based electrocatalysis electrode structure of  claim 3 , wherein the nanorods have length of approximately 80 to 300 nanometers. 
     
     
         5 . The three-dimensional non-noble-metal-based electrocatalysis electrode structure of  claim 1 , wherein the anisotropic nanochannels have a channel width of approximately 50-150 nanometers. 
     
     
         6 . The three-dimensional non-noble-metal-based electrocatalysis electrode structure of  claim 1 , wherein the non-noble metal is one or more of iron, cobalt, nickel, copper, molybdenum, or tungsten. 
     
     
         7 . The three-dimensional non-noble-metal-based electrocatalysis electrode structure of  claim 1 , wherein the one or more layers of fused and approximately aligned elongated electrocatalyst nanoparticles are 3-D printed elongated electrocatalyst nanoparticles, and each layer has a thickness of approximately 50 to 200 microns. 
     
     
         8 . The three-dimensional non-noble-metal-based electrocatalysis electrode structure of  claim 7 , wherein the one or more layers of fused and approximately aligned elongated electrocatalyst nanoparticles are deposited on a substrate. 
     
     
         9 . The three-dimensional non-noble-metal-based electrocatalysis electrode structure of  claim 8 , wherein the substrate is a current collector selected from carbon, graphite, copper, or nickel. 
     
     
         10 . A method for making the three-dimensional non-noble-metal-based electrocatalysis electrode structure of  claim 1 , comprising:
 3-D printing elongated electrocatalyst nanoparticles of a non-noble metal alloy or non-noble metal compound to deposit one or more approximately aligned elongated electrocatalyst nanoparticle layers;   fusing the approximately aligned elongated electrocatalyst nanoparticles at an elevated temperature to create a fused structure having anisotropic nanochannels configured to transfer generated gas bubbles therethrough.   
     
     
         11 . The method of  claim 10 , further comprising forming elongated electrocatalyst nanoparticles by hydrothermal synthesis. 
     
     
         12 . The method of  claim 11 , wherein the hydrothermal synthesis includes reacting non-noble metal salt precursors at an elevated temperature and pressure to precipitate the non-noble metal-based elongated electrocatalyst nanoparticles. 
     
     
         13 . The method of  claim 12 , wherein precipitated elongated electrocatalyst nanoparticles are combined with a surfactant and subjected to extrusion-based 3-D printing to align the elongated electrocatalyst nanoparticles in the deposited layer. 
     
     
         14 . The method of  claim 10 , wherein fusing the approximately aligned elongated electrocatalyst nanoparticles at an elevated temperature is performed at a temperature of 300-700° C. 
     
     
         15 . The method of  claim 10 , further comprising a reducing treatment following the fusing of the elongated electrocatalyst nanoparticles at elevated temperature. 
     
     
         16 . The method of  claim 10 , wherein the elongated electrocatalyst nanoparticles are nanorods. 
     
     
         17 . The method of  claim 10 , wherein elongated electrocatalyst nanoparticles include nickel and molybdenum.