We have evaluated the process of watersplitting into hydrogen gas. Electrolysis-photocatalysis reactor is used to harvest hydrogen gas through water splitting, a combination of electrolysis and photocatalysis reactions. The concentration of hydrogen gas (H2) is detected by the MQ-8 sensor and the number of bubbles is calculated. Evaluation of watersplitting is done by varying the DC voltage source (3V, 6V, 9V, 12V). We found the highest concentration of H2 gas was produced at 12 volts 616300 ppm for 600 seconds, The largest increase from the photocatalyst-electrolysis reaction combination was found to be 182017 ppm. Here we observe a linear increase in hydrogen with increasing voltage which results in a faster electrolysis process. But what is most interesting is the increase in H2 during the simultaneous electrolysis-photocatalysis process. the combined reaction has increased the amount of hydrogen greater than the sum of the photocatalytic and electrolysis reactions taking place separately. It is most likely that a mutually reinforcing reaction occurs so that the overall activation energy of the system becomes smaller in the process of dissociating water into hydrogen.