High-throughput screening of materials for electrocatalysis is necessary for developing the next generation energy solutions. Identification of new stable catalysts requires this high-throughput screening of material composition and particle size to understand the fundamental reaction mechanisms as well as the physical and chemical properties [1,2]. Understanding and developing these novel nanomaterials will help to develop the technical improvements for energy storage and fuel cells.
The challenge with developing these experiments is synthesizing samples in a reproducible way. For example, the surfactant assisted seed-growth synthesis of nickel and iron catalysts has significant impacts on the morphology and stability of the nanoparticles and removing the surfactants and other contaminants inherent with these synthesis techniques is challenging. The process is difficult, time consuming and often yields irreproducible results .
To address these challenges, VSParticle developed the VSP-G1 nanoparticle generator using spark ablation technology. Capable of creating chemically pure sub 20 nm particles with controlled size, the experimental set-up detailed below provides a new solution to generate, deposit and evaluate the composition of pure or alloyed nickel and iron nanoparticles.
The material composition and loading of materials have an influence on the efficiency of the electrocatalysts. In this experiment, it is demonstrated that the deposition of ligand-free nanoparticles onto a high-throughput chip is possible with the VSP-G1 and the VSP-P1 printer depositing the varying nanoparticle compositions as a 2D array.
Figure 1: VSParticle nanoparticle generator VSP-G1 setup in parallel with the VSP-P1 nanopourous printer to print inorganic nanostructured materials on any substrate.
Setup of nanoparticle deposition for high-throughput screening
An array of 8×8 dots were printed onto a nickel substrate designed for high-throughput analysis. The effect of the deposition time and composition on the Oxygen Evolution Reaction (OER) imaged below shows the cell potential versus the nickel-iron nanoparticle ratio and deposition time.
Figure 2: The measured cell potential (contours) as a function of Ni/Fe ratio and deposition time (deposited mass).
Two VSP-G1 units were connected in parallel to the VSP-P1 unit. By varying the voltage, current, and carrier gas flow rate though the two units, the relative composition of the material was controlled.
The nanoparticle aerosol is led into a vacuum chamber where a portion of the aerosol is used for printing. The deposited dots have a diameter of about 3 mm.
The amount of deposited material is controlled by the deposition time, varying from 1-320 s.
Pure Synthesized Nanoparticle Result in Faster More Accurate Results
The screening shows an optimum where the cell potential is lowered from 2.60 V to 2.32 V.
With the combination of a printing and screening system, it is possible to drastically reduce catalyst development time.
Figure 3: Plots of the measured cell potential versus total deposition time (deposited mass) are shown for the 8 Ni/Fe ratios generated.
-  https://www.anl.gov/cse/discovery-acceleration
-  A. Shinde, et al. Electrocatalysis 6 (2015) 229-236. https://link.springer.com/article/10.1007/s12678-014-0237-7
-  S.S. Alruqi, S.A. Al-Thabaiti, Z. Khan. J. Mol. Liq. 282 (2019 448-455. https://www.sciencedirect.com/science/article/abs/pii/S0167732218355338