This study investigates the performance enhancement of electrocatalytic hydrogen evolution through coalescence-induced bubble dynamics. Using a dual platinum micro-electrode system in 0.5 M H₂SO₄, the researchers systematically study the dynamics of hydrogen bubbles produced during the hydrogen evolution reaction. By varying the electrode distance and cathodic potential, they combine high-speed imaging and electrochemical analysis to demonstrate the importance of bubble-bubble interactions for the departure process. They show that bubble coalescence can lead to substantially earlier bubble departure compared to buoyancy effects alone, resulting in higher reaction rates at constant potential. However, repeated coalescence events with bubbles close to the electrode may drive departed bubbles back to the surface beyond a critical current, increasing with electrode spacing. This leads to the resumption of bubble growth near the electrode surface, followed by buoyancy-driven departure. At larger electrode separations, this configuration proves beneficial, increasing the mean current up to 2.4 times compared to a single electrode. The study also explores the phase diagram of bubble return, showing that the probability of bubble return increases with electrode spacing and overpotential. The results indicate that coalescence-induced bubble dynamics can significantly enhance the performance of electrocatalytic hydrogen evolution, particularly at larger electrode separations. The findings suggest that further increasing electrode separation could lead to even greater performance gains. The study highlights the importance of understanding bubble dynamics in electrochemical systems and the potential for coalescence-induced bubble dynamics to improve the efficiency of hydrogen evolution reactions.This study investigates the performance enhancement of electrocatalytic hydrogen evolution through coalescence-induced bubble dynamics. Using a dual platinum micro-electrode system in 0.5 M H₂SO₄, the researchers systematically study the dynamics of hydrogen bubbles produced during the hydrogen evolution reaction. By varying the electrode distance and cathodic potential, they combine high-speed imaging and electrochemical analysis to demonstrate the importance of bubble-bubble interactions for the departure process. They show that bubble coalescence can lead to substantially earlier bubble departure compared to buoyancy effects alone, resulting in higher reaction rates at constant potential. However, repeated coalescence events with bubbles close to the electrode may drive departed bubbles back to the surface beyond a critical current, increasing with electrode spacing. This leads to the resumption of bubble growth near the electrode surface, followed by buoyancy-driven departure. At larger electrode separations, this configuration proves beneficial, increasing the mean current up to 2.4 times compared to a single electrode. The study also explores the phase diagram of bubble return, showing that the probability of bubble return increases with electrode spacing and overpotential. The results indicate that coalescence-induced bubble dynamics can significantly enhance the performance of electrocatalytic hydrogen evolution, particularly at larger electrode separations. The findings suggest that further increasing electrode separation could lead to even greater performance gains. The study highlights the importance of understanding bubble dynamics in electrochemical systems and the potential for coalescence-induced bubble dynamics to improve the efficiency of hydrogen evolution reactions.