The addition of 1,4-benzoquinone and Fe3+ to [Pd(1,10-phen)(2)](2+) catalyst systems has been undertaken to assess the ability of these oxidants to increase the ethene dimerisation turnover of Nafion immobilised Pd(II) catalysts. Although 1,4-benzoquinone increases the turnover of the Pd(II) catalyst in methanol, it deactivates the catalyst in water. Fe3+ ions have, however, been found to extend the life of the Pd(ll) catalyst in water. Fe3+ is effective both in homogeneous solution and when incorporated into Nafion with [Pd(1,10-phen)(2)](2+).