To understand the catalytic activity of produced GdTe crystal, its ability of splitting the water to generate hydrogen without external energy is demonstrated. A large number of hydrogen bubbles were generated immediately as GdTe reacts with water at room temperature (Figure and movie S1). In the beginning, a steady HER rate of ~0.022 μmol min -1 gm -1 was observed for 5 min which then increases rapidly after 10 min where eventually ~1.0 g of GdTe produced more than ~1.87 µmol of H2 within 30 min (Figure ). Along with water, GdTe also reacts with dry methanol and produced H2 with slower rate (Figure ). Moreover, GdTe shows the most favorable onset potential when compared with state-of-the-art HER catalyst (Figure ) .