The progress of nanotechnology has encouraged scientists to continuously develop electrode materials for constructing an improved electrochemical platform for sensing and energy devices. Therefore, many researches have been performed to develop the supporting electrode materials for high performing nanostructured hybrid electrodes in sensing and energy devices. The interaction between nanotechnology and biotechnology has paid a great attention the development of electrochemical sensing devices for diagnostics. In particular, the suitable immobilized nanostructured platform with high catalytic active area is a key important for enzymatic electrochemical devices. For the practical applications, enzymatic electrochemical devices are still challenging in sensing performance such as sensitivity, stability, and selectivity. It is of much importance to explore stable bio-matrix for enzyme immobilization, and exploiting higher accuracy and productivity of the enzyme activity. In these works, various reduced graphene oxide as supporting electrode materials and nanoparticles as catalytic active materials were developed and characterized for hybrid nanostructured electrodes to be used in the electrochemical sensing and energy devices.Initially, the electrochemically reduced graphene oxide (ERGO) was prepared by electrochemical treatment in the electrolyte solution, which is a fast and controllable process due to the high cathodic reduction of oxygen functional groups of chemically modified graphene oxide on the surface of a gold substrate electrode in alkaline solution. Then, Pd nanoparticles (NP) were deposited by electrochemically, which were dispersed homogeneously on the surface of ERGO. The fabricated hybrid electrode exhibited good analytical properties in terms of a short response time of 3 s, high sensitivity (512.5 μA/mMcm2, and linear range from 0.05-8 mM for hydrogen peroxide (H2O2) in PBS solution and response time of 3 s, sensitivity of 15.14 μA/mMcm2, and linear range from 0.05-10 mM for glucose sensing in sodium hydroxide solution.Secondly, the highly hybridized reduced graphene oxide was developed by chemically and thermally. Then, bimetallic nanoparticles (PtPdNP) were deposited by electrochemically at 55 mC control charge on the RGO surface for obtaining high catalytic active surface area. The PtPdNP was well dispersed in the RGO network, forming an interpenetrating network for favorable conduction pathways and electron transfer kinetics. The as-prepared hybrid electrode exhibited high electrocatalytic activities toward H2O2 reduction, to which it had a wide linear response ranging from 0.5 to 8 mM, a response time of 2 s and high sensitivity of 814 μA/mMcm2 and H2O2 oxidation along with a response time of 3 s, linear detection in the range of 0.5 mM to 6.5 mM, and a sensitivity of 486 μA/mMcm2 were found at 0.55 V. In addition, glucose oxidase (GOx) was immobilized on the hybrid electrode platform by the way of crosslinking. The as-prepared enzymatic electrode showed high electrocatalytic activity toward glucose oxidation, with a response time of 5 s, sensitivity of 24 μA/mMcm2, and linear range of 2-12 mM for glucose oxidation.Thirdly, the chemically modified reduced graphene oxide (CRGO) was synthesized by chemical treatment of exfoliate graphite oxide and heat treatment of CRGO film and bimetallic nanoparticles (PtPdNP) were co-deposited electrochemically on the surface of CRGO modified electrode without using any surfactant or ionic electrolyte at 55 mC control charge. The electroactive surface area (ESA) for the CRGO modified electrode and CRGO/PtPdNP electrode is estimated to be 1.16 cm2 and 52.24 cm2, respectively. The as-prepared hybrid electrode exhibited high electrocatalytic activities toward oxidation of hydrogen peroxide, with a wide linear response range from 0.5-8 mM and high sensitivity of 437.06 μA/mMcm2. Furthermore, glucose oxidase with chitosan composites was immobilized on the surface of the CRGO/PtPdNP hybrid electrode by covalently. To increase the selectivity and stability of the biosensor, nafion coating was coated on the surface of the CRGO/PtPdNP/Ch-GOx modified electrode. The as-prepared biosensor showed good amperometric response to glucose in the linear range from 0.5 mM to 11 mM with a sensitivity of 11.81 μA/mMcm2, low detection limit of 0.003 mM (signal to noise ratio is 3), and a short response time of 3 s. Moreover, the effect of interference materials and the stability of the sensor were also investigated of four weeks.Fourthly, hydrothermally reduced graphene oxide (TRGO), and glucose treated reduced graphene oxide and activated carbon (GRGO/AC) composites were synthesized by hydrothermal technique and substituted on the microelectrodes system. Series connected distributed sensing electrodes and rectangular electrode were fabricated and decorated with TRGO and GRGO/AC, respectively. PtNP, and chitosanenzyme composites (adsorbed) and nafion were integrated onto the TRGO/PtNP modified distributed surface for effectively glucose sensing. The as-fabricated distributed electrode based glucose sensor demonstrated a good amperometric response to glucose with a sensitivity of 41.18 μA/mMcm2, a short response time of 5 s, and stability of 4 weeks. The GRGO/AC modified surface was decorated by PtNP and chitosan-enzyme composites (covalently) with nafion. The rectangular type glucose sensor exhibited in the detection range from 0.002 mM to 10 mM, with a sensitivity of 61.06 μA/mMcm2, a short response time of 4 s, a low detection limit of 2 μM (signal to noise ratio is 3) and negligible interference effect. For practical assessment, both sensor were tested in urine glucose and showed acceptable performance for the detection of routine urine glucose.Finally, the electrochemical deposition of Ni(OH)2 on highly hybridized RGO was more effective to improve the catalytic activity of electrode and to increase the capacity performance of the electrochemical pseudocapacitor. The as-obtained supercapacitor exhibited the specific capacitance of 729 mF/cm2, power density of 1.5 mW/cm2 and long-term cycling stability. Cyclic voltammetery and the amperometric method were applied to evaluate the catalytic performance of the reduced graphene oxide sheets withnanoparticles modified electrodes in terms of the electrocatalytic oxidation of ethanol. The current density of RGOs/PtPdNP catalyst was measured of 120.2 mA/cm2. Moreover, the onset potential of this electrode was of -0.671 mV with a forward and backward current ratio of 1.7.