International Journal of Latest Research in Engineering and Technology (IJLRET) ISSN: 2454-5031 www.ijlret.com || Volume 02 - Issue 09 || September 2016 || PP. 60-66 www.ijlret.com 60 | Page Cu-Pd Bimetallic Catalyst for Electrocatalytic Reduction of Nitrates in Water Bren Mark B. Felisilda, Louis Hamenu, Jeong Ho Park, Chung Sup Yoon, Jang Myoun Ko 1 Department of Chemical and Biological Engineering, Hanbat National University, San 16-1 Deokmyeong-dong, Yuseong-gu, Daejeon 305-719, South Korea 1 Corresponding Author: Jang Myoun Ko Abstract: This paper reports the use of bimetallic catalysts, prepared via co-electrodeposition of Cu and Pd from chloride baths in 0.5 M HNO 3 on Ti substrates and its catalytic effect on nitrate reduction. Electrochemical measurements were made using cyclic and linear sweep voltammetry while deposition was made via chronopotentiometry at -0.5 V vs Ag/AgCl. Scanning electron microscopy analyses revealed that the films produced by potentiostatic deposition are porous and rough, which is suitable for electrocatalysis applications. Results show that prepared electrocatalyst was able to reduce nitrates with 86.50% efficiency after 3 hours. Meanwhile, soaking the electrocatalyst in tap water over time decreases its efficiency to some extent but still capable of reducing high concentration of nitrates in water. Keywords: potentiostatic electrodeposition; bimetallic catalyst; electrochemical reduction; nitrates 1. Introduction Many rivers, lakes and ground waters are continuously being contaminated with nitrates from misused fertilizers and industrial wastes. This poses an important problem not only for human health but also for the ecosystems. When inside the human body, nitrates can be reduced to nitrites that combine with hemoglobin to form methemoglobin, which can be deadly to newborn babies [1]. The need to regulate or remove such ions has stimulated intensive research from reduction techniques to reaction mechanisms. Methods used for nitrate reduction are classified under physico-chemical, biological and electrochemical [2]. Examples are biological denitrification and ion exchange. But these methods have known drawbacks like the need for continuous monitoring, slow kinetics and by-product formation [2]. Recently, researchers have given more focus on electrochemical methods due to good efficiency, low cost and lesser reagents. Reducing the nitrate ion is one of the few ways to regulate or remove such pollutants from water and electrochemical reduction of nitrates gives a relatively broad spectrum of products. This tells us that the mechanism behind the reduction is not easy. However, many ways were developed to optimize the parameters behind the process. The catalytic reduction with hydrogen was one of the first methods to garner attention [3]. Monometallic catalysts were also used but bimetallic catalysts were found to be more efficient in heterogeneous catalytic reduction of nitrates [4, 5]. The catalyst is usually composed of a noble metal, mainly Pd or Pt but also Ru, Rh or Ir, and a promoter metal, such as Cu, Sn, Ag, Ni, In or Fe, on different supports like alumina, silica and activated carbon [6]. Among them, Pd- Cu, Pd-Sn and Pt-Cu seem to be more effective but lack selectivity to nitrogen [7]. Moreover, the method of preparation, the metal/promoter ratio, the operation conditions and the interaction between metals control the catalyst’s activity and selectivity [8]. For the past years, copper-palladium alloys have gained the spotlight due to their widespread potential use in many electrocatalytic applications. Many papers have been published dealing with various techniques for the deposition of bimetallic/alloy copper-palladium coatings like sputtering, chemical vapor deposition and pulsed- laser techniques [9, 10]. But these methods were limited for laboratory investigations and not into large scale production. On the other hand, electroless plating and electrodeposition are two preparation methods that offer good results for small and large scale productions. While a number of researches have been done in this area, but very few have been published on co-electrodeposition of Cu-Pd alloys. Notably, Reyter et al. [2] and Milhano and Pletcher [11] were able to co-electrodeposit Cu-Pd alloys over a wide range of composition from nitrate-based and sulfate-based baths respectively. This study presents Cu-Pd alloys prepared via co-electrodeposition using chloride-based baths. Potentiostatic electrodeposition was carried out and scanning electron microscopy (SEM) with energy dispersive X-ray spectroscopy (EDXS) were used to characterize the Cu-Pd deposits. Then, the effect of the prepared electrocatalyst was investigated on nitrate reduction efficiency.