A variety of nanostructured materials are produced through template-based synthesis methods, including zerodimensional, one-dimensional, and two-dimensional structures. These span different forms such as nanoparticles, nanowires, nanotubes, nanoflakes, and nanosheets. Many physical characteristics of these materials such as the shape and size can be finely controlled through template selection and as a result, their properties as well. Reviewed here are several examples of these nanomaterials, with emphasis specifically on the templates and synthesis routes used to produce the final nanostructures. In the first section, the templates have been discussed while in the second section, their corresponding synthesis methods have been briefly reviewed, and lastly in the third section, applications of the materials themselves are highlighted. Some examples of the templates frequently encountered are organic structure directing agents, surfactants, polymers, carbon frameworks, colloidal sol-gels, inorganic frameworks, and nanoporous membranes. Synthesis methods that adopt these templates include emulsion-based routes and template-filling approaches, such as self-assembly, electrodeposition, electroless deposition, vapor deposition, and other methods including layer-by-layer and lithography. Templatebased synthesized nanomaterials are frequently encountered in select fields such as solar energy, thermoelectric materials, catalysis, biomedical applications, and magnetowetting of surfaces.

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to be generated in an environmentally benign manner.Fuel cells are electrochemical devices which convert the chemical energy produced by an electrochemical reaction into electricity. Polymer electrolyte membrane fuel cells (PEMFCs) are one of the most promising systems, and they have been used for stationary and automobile applications as well as for small scale portable devices. Hydrogen as a fuel and oxygen as an oxidant are the most common reactants used for these fuel cells. Other fuels such as methanol and formic acid are also used in PEMFC. The heart of fuel cells is the membrane electrode assembly (MEA) which is composed of two electrodes, the anode and the cathode, and the electrolyte. The electrolyte is a proton exchange membrane (PEM) which allows protons to pass through from anode to cathode side. The membrane needs to have high proton conductivity, electrical insulation, thermal and mechanical strength; it needs to be light weight, flexible, have low permeability to reactant species, resistance to fuel transport, highly durable and facilitate quick electrode kinetics, suitable for use with different fuels, and low in cost. The electrolyte in a fuel cell has three main functions, to act as ion conductor, electronic insulator, and a separator for the reactant gases. [4] Nafion is the most widely used polymeric membrane in PEMFC. It has a particular structure which requires hydration leading to high proton conductivity. It cannot be used at temperatures beyond 100 °C since the proton conductivity decrease when Nafion is not perfectly hydrated. Another drawback of Nafion is fuel crossover, which is the permeability of the fuel from the anode side to the cathode side leading to a decrease in the efficiency of the fuel cell. This particular problem is more significant in direct methanol fuel cells (DMFC) which use methanol as a fuel which can easily permeate through Nafion. In all fuels contexts, great efforts have been made to find a new electrolyte membrane which can replace Nafion, and 2D materials can play an important role in this.Graphene is the name given to a flat monolayer of carbon with a 2D honeycomb lattice and is the basic building block for graphitic materials of all other dimensionalities. [5] It has particular properties such as notably high surface area around 2630 m 2 g −1 , [1,6] exceptionally high electrical conductivity, 104.36 S cm −1 , [1,7] high flexural strength, 44.28 MPa, [1,8] and good chemical and thermal stability, [1,9] which make it a potential material for a large number of applications.The isolation of graphene is considered as the beginning of a new generation of 2D materials and 2D crystals. Because of their particular layered structure, with planar topology and a thickness from single to few atomic layers, which provide them with unique properties, 2D material are expected to have important applications in the next generation of energy systems. Electrochemical energy storage devices such as batteries or supercapacitors have already incorporated these materials as electro...