dcat-admin2/src/Form/Field/Time.php

<?php

namespace Dcat\Admin\Form\Field;

class Time extends Date
{
    protected $format = 'HH:mm:ss';

    public function render()
    {
        $this->prepend('<i class="fa fa-clock-o fa-fw"></i>')
            ->defaultAttribute('style', 'width: 200px');

        return parent::render();
    }
}