## 3 Results
The cell voltage measurements are presented in Figure 7.  
Cell voltage measurements were conducted at both room temperature and an elevated temperature of 60 \({}^{\circ}\)C. The curves obtained exhibit characteristic behavior typical of electrochemical hydrogen pump/compressor (EHP/C) devices. At 20 \({}^{\circ}\)C, the process initiates at around 10 mV, and with an increase in cell voltage, the current density progressively rises. At a cell voltage of 0.25 mV, diffusion limitations are observed. As the temperature rises, \begin{table}
\begin{tabular}{c c c} \hline
**Sample** & **Active Area** & **Overpotential** \\  & **[cm\({}^{2}\)]** & **[V]** \\ \hline Pt/MPT 10\% wt. & 1.02 & \(-\)0.063 \\ Pt/MPT 20\% wt. & 1.12 & \(-\)0.063 \\ Pt/MPT 30\% wt. & 1.18 & \(-\)0.059 \\ Pt/MPT 40\% wt. & 1.25 & \(-\)0.058 \\ \hline \end{tabular}
\end{table} 
Table 3: Active surface area calculated by cyclic voltammetry. Figure 7: Cell voltage measurements of MEA with 30 wt.% Pt/MPT as cathode and 40 wt.% Pt/XC72 as anode, at 20, 40, and 60 \({}^{\circ}\)C.  
the ionic transport between the anode and cathode intensifies, leading to an acceleration in both the hydrogen reduction reaction (HRR) and hydrogen oxidation reaction (HOR) rates. At 40 \({}^{\circ}\)C, the maximum current density peaks at 160 mA cm\({}^{-2}\), while at 60 \({}^{\circ}\)C, this value further increases to 260 mA cm\({}^{-2}\). The compression tests up to 3 bar were carried out in the temperature range from 20 \({}^{\circ}\)C to 60 \({}^{\circ}\)C at 60 mA cm\({}^{-2}\). The curves are presented in Figure 8a,b. An elevation in the differential pressure corresponds to an increase in the cell voltage of the electrochemical hydrogen pump/compressor (EHP/C) [54]. The investigated membrane electrode assembly (MEA) displays a cell voltage of 60-70 mV at 60 mA cm\({}^{-2}\) and demonstrates the capability to operate more effectively under the higher temperature. As the temperature rises, there is a noticeable reduction in the cell voltage, indicating an increase in the energy efficiency. The increase in cell voltage per bar calculated from the U\({}_{\text{EHC}}\)/P\({}_{\text{diff}}\) curves is presented in Figure 8b. Elevating the operating temperature not only improves the efficiency of the electrochemical hydrogen pump but also leads to a reduction in cell voltage per bar. This suggests that employing higher temperatures makes it possible to increase the final pressure of the hydrogen converter. Specifically, at 20 \({}^{\circ}\)C, the cell voltage increases by 0.0047 V per bar, while at 60 \({}^{\circ}\)C, this value decreases to 0.0037 V, indicating a 0.001 V enhancement in efficiency. In comparison with MEAs with commercial Pt/XC72 catalysts, the newly developed materials show better performance and low overpotential under compression mode. The curves are presented on Figure 9.  
The integration of the newly synthesized Pt/MPT 30% wt. catalyst as the cathode improves the efficiency of the MEA. It decreases the cell voltage during the pumping process, with approximately 0.04 V at 1 bar of differential pressure and 0.05 V under 3 bar of differential pressure. Figure 8: (**a**) Influence of pressure on MEA performance (30 wt.% Pt/MPT cathode, 40 wt.% Pt/XC72 anode) at constant current of 60 mA\(\cdot\)cm\({}^{-2}\) with maximum deviation below 3.2% (**b**) Change in cell voltage per bar with temperature.