Electrochemical synthesis of hollow gold nanoparticles on the pencil graphite electrode surface as high efficient cathode for hydrogen production

The worry that always have been existed in using the fossil fuels such as; scarce resources and air pollutant problems, makes the human being to revise about his life style. The idea of using hydrogen as a clean energy is considered to be the best way to prevent the appearance of fossil fuel usage outcomes. Although it is the most common element in the world, hydrogen is found in impure form on our planet combined with oxygen as water and combined with carbon and other elements in fossil fuels and innumerable hydrocarbon compounds [1]. A fuel cell is an accessible device to produce hydrogen green energy and we are interested to apply procedures in order to decrease the overvoltage of hydrogen evolution reaction (HER) which occur during the electrochemical process in the cell. Up to now, much attention has been focused on exploiting transition metal alloys, carbides, nitrides, phosphides, sulphides and so on for catalysis the HER [2]. Platinum is one of the best catalysts for HER but the drawbacks that limited it’s practical application is it’s high costs and rare resources so the researcher’s interest is focused on other earth-abundant noble metals.In this work reduced graphene oxide (rGO) was deposited electrochemically on the surface of a single-use pencil graphite electrode (PGE). The main reason for choosing the disposable PGE is the ease of preparation, commercial availability, and low costs [3]. Then cobalt nanoparticles (CoNPs) which they act as a sacrificial template, were placed on the rGO surface by the use of electrochemically deposition method after that hollow Au nanoparticles (HAuNPs) were produced using a galvanic replacement reaction between Au3+ ions with CoNPs. The advantages of using HAuNPs instead of AuNPs are magnitude surface active area and subsequently lower consumption of gold. In this study the overvoltage of hydrogen evolution reaction in acidic medium on modified electrode was decreased. Exchange current density and electron transfer coefficient were obtained as 6.01×10-5 (mA/cm2) and 0.4, respectively.