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Page 12 of 21 Chen et al. J Mater Inf 2022;2:19 https://dx.doi.org/10.20517/jmi.2022.23

Figure 8. (A) Schematic illustration of combinatorial and HT synthesis of uniform MMNCs. (B) Scanning droplet cell setup and
patterned samples on copper substrate. (C) Fast screening of PtPd-based MMNCs for catalytic ORR (22 compositions + one blank, 0.1
M KOH, 5 mV/s scan rate). (D) Compositional designs and their corresponding ORR performance are presented in a neural network
diagram. The size of the circles represents the magnitude of the specific current at 0.45 V for ORR. (E) Data-driven discovery cycle
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combines prediction, combinatorial synthesis and HT characterization. (A-D) Reproduced with permission . Copyright 2019, Science.
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(E) Reproduced with permission . Copyright 2021, Wiley-VCH. CE: counter electrode; RE: reference electrode; WE: working
electrode.
number of adsorption sites with different chemical environments results in the large variance in the
adsorption energies of N*. This means that such a wide variation requires training the data set with a wide
range of different systems, thereby increasing the training time for accurate ML. To consider the symmetry
of active sites, the data set was extended by 10%-25%. Taking the HCP-hollow site as an example, little
variation in the adsorption energy can be observed when changing the arrangement of three
nearest-neighbor elements around the adsorption site. A ratio of 80%/20% for the training/testing data set
was selected to build the convolutional neural network model. The high accuracy of the convolutional
neural network model is demonstrated by a mean absolute error (MAE) of 0.05 eV per nitrogen atom.
Furthermore, there is no systematic bias in these predictions, suggesting that the accuracy of the neural
network model is absolutely comparable to the intrinsic accuracy of DFT calculations, which is used for the
generation of the training data set. The catalytic activity of CoMoFeNiCu for ammonia decomposition and
synthesis was optimized, where Co Mo Fe Ni Cu with x:y ratios of 25:45-35:35 have a similar nitrogen
x y 10 10 10
binding energy to that of Ru (0001). Recent experimental results also indicated that Co Mo Fe Ni Cu is a
25
45
10
10
10
[20]
high-performance catalyst towards ammonia decomposition .
ML models of ORR on HEA catalysts
The Rossmeisl group performed HT DFT calculations for the adsorption energies of OH* and O* on 871
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and 998 different 2 × 2 unit cells of IrPdPtRhRu HEAs, respectively, as summarized in Figure 9A and B .