## 3 Results
The cyclic voltammograms recorded within the typical potential window for hydrogen energy devices in 0.5 M H\({}_{2}\)SO\({}_{4}\) are depicted in Figure 5. \begin{table}
\begin{tabular}{c c c c c} \hline \hline \multirow{2}{*}{**Sample**} & \multicolumn{4}{c}{**Crystal Size**} \\ \cline{2-5}  & \multicolumn{2}{c}{**(111)**} & \multicolumn{2}{c}{**(200)**} \\ \cline{2-5}  & **FWHM** & **Width** & **FWHM** & **Width** \\ \hline Pt/MPT 10\% wt. & 16 (2) & 12 (2) & 11 (1) & 10 (1) \\ Pt/MPT 20\% wt. & 18 (1) & 13 (1) & 12 (1) & 10 (1) \\ Pt/MPT 30\% wt. & 16 (1) & 12 (1) & 12 (1) & 9 (1) \\ Pt/MPT 40\% wt. & 13 (1) & 9 (1) & 9 (1) & 7 (1) \\ \hline \hline \end{tabular}
\end{table} 
Table 1: Particle size calculations of the synthesized samples. \begin{table}
\begin{tabular}{l c c c c} \hline \hline \multirow{2}{*}{**Characteristics**} & **Pt/MPT** & **Pt/MPT** & **Pt/MPT** & **Pt/MPT** \\  & **10\% wt.** & **20\% wt.** & **30\% wt.** & **40\% wt.** \\ \hline Surface area MP [m\({}^{3}\)/g] & 15.3 & 17.5 & 9.8 & 7.7 \\ Surface area SP [m\({}^{3}\)/g] & 13.0 & 13.4 & 8.7 & 6.0 \\ Total pore volume [cm\({}^{3}\)/g] & 0.037 & 0.039 & 0.023 & 0.018 \\ Average pore diameter [nm] & 9.7 & 9 & 9.2 & 9.5 \\ \hline \hline \end{tabular}
\end{table} 
Table 2: BET analysis/results of the produced samples. The cyclic voltammograms exhibit characteristic peaks indicative of Pt-based catalysts. In the anode side corresponding to the hydrogen oxidation reaction (HOR), the peak shape aligns with the crystallographic orientation (111) as determined from XRD measurements [52]. The peak intensity shows an increasing trend, with higher Pt content on both the anode and cathode sides, where the hydrogen evolution reaction occurs. The Pt/MPT samples with 10% wt. and 20% wt. show the lowest activity. The samples with 30% wt. and 40% wt. demonstrate comparable electrochemical activity for both hydrogen evolution and hydrogen oxidation reactions, which are crucial for EHP/C technology. The calculated active surface areas, derived from the cyclic voltammograms in Figure 5 using the methodology in [53], and the overpotential related to HRR calculated from data in Figure 6, are both presented in Table 3.  
Figure 5: Cyclic voltammograms of Pt/MPT catalysts (10–40 wt.% Pt) recorded at \(-\)0.2 V to 1.8 V vs. RHE; scan rate: 50 mV s\({}^{-1}\), 20 \({}^{\circ}\)C, 0.5 M H\({}_{2}\)SO\({}_{4}\). Figure 6: Linear voltammograms of Pt/MPT catalysts (10–40 wt.% Pt) recorded at 0.4 V to \(-\)0.3 V vs. RHE; scan rate: 1 mV s\({}^{-1}\), 20 \({}^{\circ}\)C, 0.5 M H\({}_{2}\)SO\({}_{4}\). All examined samples exhibit nearly identical electrochemically active surface areas with small discrepancies in the decimal values. In order to investigate the catalytic activity of the prepared flat electrodes in detail, potential dynamic curves were recorded at potential windows of 0.4 V up to \(-\)0.3 V vs. RHE, with a scan rate of 1 mV s\({}^{-1}\). The results are presented in Figure 6.  
Uniform trends are evident across all samples with respect to their behavior and polarization during the hydrogen evolution reaction in the acidic electrolyte. Specifically, samples with 10% wt. and 20% wt. of platinum display a relatively modest current density of around 40 mA cm\({}^{-2}\). By contrast, samples containing 30% wt. and 40% wt. show a nearly twofold increase in current density. The overpotential for the hydrogen reduction reaction in all synthesized samples is measured relative to the reference hydrogen electrode (RHE). In conclusion, the Pt/MPT sample with 30% wt. emerges as the most favorable, exhibiting the highest current density and optimal utilization of Pt catalysts. Following the screening process, membrane electrode assemblies (MEAs) were developed, incorporating Pt/MPT as catalysts for the hydrogen reduction reaction and commercially available Etek Pt/XC82 40% wt. for the hydrogen oxidation reaction. This MEA was integrated into a self-assembled electrochemical hydrogen compressor cell equipped with two reference electrodes to ensure precise control and diagnostics.