LAUSR

A new reduced graphene oxide (rGO) based bi‐phasic crystal of MnO2, namely α‐MnO2 nanorods and δ‐MnO2 nanoflakes containing heterostructured hybrid nanoflower rGO@α‐MnO2/rGO@δ‐MnO2 has been fabricated through a facile hydrothermal method followed by annealing treatment. The successful synthesis of the hybrid material was studied by XRD, Raman, BET, FESEM with EDX, FTIR and TEM analyses. An efficient N‐alkylation reaction of substituted aromatic amines with aromatic alcohols was carried out under solvent‐free aerobic conditions in the presence of catalytic amount of rGO@α‐MnO2/rGO@δ‐MnO2. The catalyst shows excellent activity in terms of high yields (up to 98 %), short reaction time (10 h) along with a simple work‐up process. The spent material can be regenerated several times without causing any serious decrease in catalytic activity. Moreover, cyclic voltammetry (CV), galvanostatic charge‐discharge (GCD), and cyclic stability techniques were executed to evaluate the performances of rGO@α‐MnO2, rGO@δ‐MnO2, and rGO@α‐MnO2/rGO@δ‐MnO2 as energy storage materials. Among all those materials, rGO@α‐MnO2/rGO@δ‐MnO2 exhibited a proficient specific capacitance, CS (267 F/g at 1 A/g) along with excellent cycling ability (∼83 % retention up to 10000 cycles). The superb electrochemical performance of rGO@α‐MnO2/rGO@δ‐MnO2 might be ascribed to the combination of bi‐phasic α‐MnO2 and δ‐MnO2 with rGO sheets, resulting in a flower‐like structure.