Question for a Wordpress Expert

I'm using the isotope jquery plugin and trying to achieve this effect dynamically because it will be for a premium theme: http://themetrust.com/demos/reveal/

In order to do this, I need to somehow add a "data-filter" attribute to the links outputted by

<?php wp_list_categories( array('taxonomy' => 'portfolio_category', 'title_li' => '', 'echo' => 1) ); ?>

and have the data-filter="THE CATEGORY NAME" dynamically.

Here is another example of what I'm trying to achieve:

http://themes.premiumpixels.com/scope/?page_id=1121

If you look at the source code of this theme, you can see:

<li class="cat-item cat-item-9"><a href="http://themes.premiumpixels.com/scope/?portfolio-type=audio" data-filter="audio" title="View all posts filed under Audio">Audio</a>
</li>

Does anyone know how to go about doing this?